I thought I saw into_play but wasn't sure enough to introduce myself, having only seen him while studying his feature matches. Anyway, I do have my report in all its lengthy glory.
I made top 64 (going 10-5) at SCG Baltimore with the following GW list, modified from maCHOOga's and lovingly dubbed "G/W Eldrazi Post" by SCG (why they can't just use what I put on the decklist form is beyond me):
4 Cloudpost, Glimmerpost, Forest
3 Green fetches
2 Vesuva, Savannah, Cavern of Souls
1 Karakas, Thespian's Stage, Khalni Garden, Eye of Ugin, Bojuka Bog, Glacial Chasm, Tabernacle
4 Primeval Titan
3 Thought-Knot Seer
1 Veteran Explorer, Reclamation Sage, Oracle
1 Old Emrakul, New Emrakul, New Ulamog
2 Ugin
4 Top, Crop Rotation
3 Green Sun's Zenith
2 Expedition Map, Swords to Plowshares, Warping Wail
Sideboard:
3 Leyline of Sanctity, Trinisphere
2 Krosan Grip, Ghostly Prison, Rest in Peace
1 Dawnstrider, Elderscale Wurm, Gaddock Teeg
Comments on card choices
I deliberately veered from my Ancient Stirrings builds in favor of a GSZ one. I didn't like and don't own Ancient Tombs, so I replaced them with the ever-powerful Khalni Garden and Bojuka Bog. In lieu of Tireless Tracker I used Rec Sage to have a game-one answer to Chalices and hateful enchantments. I took the fearless plunge into playing zero Pithing Needles, and my skepticism on that point has been largely dispelled.
The weird green creatures are in the sideboard to get maximum value out of GSZ, since some decks just can't beat an Elderscale Wurm or a Dawnstrider. These slots used to be CoP: Red but I found that the decks against which Circles were good tended to be too fast to reliably find one of the two copies, and could pressure me into tapping low or holding up mana for too many turns. Circles also don't stop Delvers. So I decided to eschew Circles in favor of searchable bullets for troublesome matchups. This turned out to be a poor decision in view of the matchups I faced.
Round 1: 2-0 vs. Shardless BUG (Matt Quinn)
Game 1: I swords some Tarmogoyfs which buys some time, but I spin my wheels and my Top for too long and he gets Liliana up to 6. I draw Vesuva while hellbent and hold it, enticing him to plus Lili instead of ultimating her. In the most absurd topdeck I've ever experienced, I draw new Emrakul and mindslaver him into sacrificing his whole board.
SB: +2 RiP, -1 Map, -1 Tabernacle
Game 2: I get put on the back foot by a curve of creatures, but he has no FoW for my Ugin which buys time for Top to find posts + new Emrakul.
Round 2: 2-1 vs. D&T (Chris Andersen)
Game 1: I expected him to be playing Lands and kept 7 on the strength of Bojuka Bog and Crop Rotation. I get punished for this error by new Thalia and company, and cast Ugin at 3 life. I wipe the board but he vials in 3 points of power.
SB: +2 Ghostly Prison, +1 Krosan Grip, -1 Map, -1 Veteran Explorer, -1 Bojuka Bog
Game 2: I mulligan to Oracle, Top, Cloudpost, Glimmerpost, Vesuva. He has no land disruption, top finds green mana, and a parade of Cloudposts enables old Emrakul to take the game.
Game 3: Much the same, without Oracle. I got to see a few grains of my opponent's legendary salt.
Round 3: 2-0 vs. D&T (Nicholas Gekoskie)
Game 1: He vials out three creatures with two lands, so I map for Tabernacle and use it to keep his board under control while I build up posts. Eventually I get Eye->New Emrakul to make him kill all his creatures with Jitte. He bounces it with Karakas, but realizes that Tabernacle + Emrakul makes for recurring Plague Wind and scoops.
SB: +2 Ghostly Prison, +1 Krosan Grip, -1 Map, -1 Veteran Explorer, -1 Bojuka Bog
Game 2: I sense that my opponent is inexperienced in the matchup so I bait him into wastelanding a Glimmerpost, which gets rotated into a Cloudpost. From there I build up while Tabernacle slows him down. Ulamog exiles his threats and his hopes.
Round 4: 2-1 vs. U/R Delver (Stuart Brooks)
Game 1: I take a lot of damage, but can cast Primeval Titan through Cavern to stabilize if he doesn't have the lethal Price of Progress. Naturally, he does.
SB: +2 Ghostly Prison, +3 Trinisphere, +1 Krosan Grip, -1 Bog, -1 Veteran Explorer, -1 TKS, -1 New Emrakul, -2 Warping Wail
Game 2: He cantrips for 4 turns without finding a creature. I stabilize behind Chasm, gain tons of life, and establish Karakas + Ulamog to deprive him of lands for the burn spells.
-1 Trinisphere, +1 Warping Wail
Game 3: I trade off removal with his threats, and a TKS prompts a large but not lethal Price of Progress. I take a second Price and he has no other burn. Tabernacle + Prison + TKS slows down his offense apart from one Stormchaser Mage. He lands Blood Moon, and I take the opportunity to Titan a Chasm into play without losing a land, having a GSZ in hand to go get Reclamation Sage. I leave the Moon in play to lull my opponent, fetching Cloudposts off of Titan attacks while taking chunks out of his life total. I blow up the Moon, Eye for Ulamog to take out a Delver and Stormchaser, and he scoops after trying to Bolt me with the now-active Chasm in play. A very close game.
Round 5: 2-0 vs. Nic Fit (David Malafarina)
Game 1: He has double Explorer + double Therapy which severely hampers my early development. Consequently, I almost lose to Nissa, Vital Force but topdeck Crop Rotation -> Eye -> Old Emrakul + Karakas on the last possible turn.
SB: -1 Explorer, -1 Tabernacle, +2 Rest in Peace
Game 2: I keep a hand with Top and a bunch of lands, which neuters his Therapies while he ramps me with his Explorers. A standard game of Cloudposts -> Emrakul.
Round 6: 2-1 vs. Lands (Kyle Kurz)
Game 1: Maindeck Bojuka Bog pulls its weight, and Titan seals the game.
SB: +2 Rest in Peace, +1 Grip, +1 Elderscale Wurm, -1 Tabernacle, -2 TKS, -1 New Emrakul
Game 2: I mulligan to 4 and get Loam+Wastelanded out of the game.
Game 3: I Bog + RiP him into topdeck mode while my Top finds me the lands to cast Primeval Titan. Enough said.
Round 7: 1-2 vs. U/R Delver (Jacob Saracino)
Game 1: This player has Wastelands and Bomat Couriers, one of which I blow up with Rec Sage. I stabilize behind Chasm with enormous quantities of mana but no Eldrazi, and my Top shows three lands. For reasons I don't understand, my opponent just scoops anyway.
SB: +2 Ghostly Prison, +2 Trinisphere, +1 Krosan Grip, -1 Bog, -1 Veteran Explorer, -1 TKS, -1 New Emrakul, -1 Warping Wail
Game 2: I land a Ghostly Prison, but it isn't enough to stop large Stormchasers from flying over.
Game 3: I get stuck on lands and don't resolve anything relevant.
Round 8: 0-2 vs. U/R Delver (Lyle Rolfes)
Game 1: I stabilize behind Chasm but let it go at 1 life. I fade his first draw step, but the second one is the ever-present Price of Progress just before I would have taken over the game.
SB: +2 Ghostly Prison, +2 Trinisphere, +1 Krosan Grip, -1 Bog, -1 Veteran Explorer, -1 TKS, -1 New Emrakul, -1 Warping Wail
Game 2: True-Name Nemesis slips past my Thought-Knots and Price finishes the job.
Round 9: 1-2 vs. 4c Delver (Jadine Klomparens)
Game 1: She never finds a Wasteland, but Oracle finds me Cloudposts. Both Warping Wails showed up in the early turns to defuse a triple-Delver draw.
SB: +2 RiP, +2 Ghostly Prison, -1 Bog, -1 TKS, -1 Map, -1 Crop Rotation? (don't quite remember)
Game 2: I durdle around with Tops for a few turns. She has double Wasteland for my Cloudpost+Stage, followed by Surgical Extraction on Cloudpost. I resolve a TKS for information and die to True-Name.
Game 3: I cast turn 2 RiP which shuts off her T1 Deathrite and the Gurmag Angler in hand, and later blanked another Surgical. I resolve TKS and take FoW from among FoW+Angler+Bolt. I should have taken the bolt, as that would have allowed TKS to kill the Deathrite and survive to race the True-Name that followed. She plays a Wasteland which I could not bait her into using on a non-Cloudpost land so that I could respond with the Crop Rotation in hand. I never find a Cloudpost for bait and True-Name kills me again. To its credit, Ghostly Prison exacted its toll each combat though it did not affect the outcome of the game. In this match I would have liked a Pithing Needle, as it seems hard to get out from underneath an active Wasteland from a cunning opponent.
Round 10: 2-0 vs. Miracles (Daniel Miller)
Game 1: My hand has a T4 Ulamog with Zenith as backup, so I lead on Cloudpost following my opponent's play of Island-and-pass. Ulamog eats Jace + Counterbalance + Swords, but Zenith->Titan->Eye->Emrakul wins.
SB: +2 Grip, +1 Ghostly Prison, -1 Bog, -2 Crop Rotation
Game 2: I keep a slower hand and get some value from Oracle, while he digs hard for Clique + Karakas. After a few repetitions of draw-Clique, I screw up my Top ordering and end up drawing old Emrakul off of a Clique draw. I decide to play some mind games and slyly spin the Top on his end step. He tanks in my draw step, decides not to Clique me on the key turn, and loses as a result. Many laughs were had.
Round 11: 2-0 vs. Lands (Travis Downes)
Game 1: Maindeck Bog takes the game again. My opponent has clearly not seen my kind of deck before and doesn't realize what lines he should be taking.
SB: +2 Rest in Peace, +1 Grip, +1 Elderscale Wurm, -1 Tabernacle, -2 TKS, -1 New Emrakul
Game 2: I deploy a Cloudpost to entice Wasteland so I can Rotate->Bog to snag both a Loam and a Wasteland. He kindly obliges but puts a Loam for nothing in the graveyard. I spin into a Vesuva to snag the second Loam which reduces him to topdecking while I have Oracle + Top. My top cards have almost no lands though, so he gets enough time to Gamble for Depths and threaten Marit Lage. I Zenith for 0 to shuffle, find Thespian's Stage, and play it with mana to copy. After the staring contest continues for a couple turns I turn my Stage into a Cloudpost to enable Ulamog, and my opponent seizes the opportunity/takes the bait to produce the 20/20. I Ulamog it and his Exploration and win from there.
Round 12: 1-2 vs. eldrazi (Matthew Long)
Game 1: I Swords his T1 Matter Reshaper, Zenith for and block with Explorer, and get to Titan for Glimmerposts to enable Ulamog. A satisfying win, as I chose this build to better fight this menace.
SB: +2 Ghostly Prison, +2 Grip, +1 Dawnstrider, +1 Elderscale Wurm, -2 Ugin, -2 Warping Wail, -1 Bog, -1 TKS
Game 2: I get run over by Mimic into double TKS, with a Wasteland that negated my potential topdecks.
Game 3: I chump some early attacks and deploy Chasm at 17 life. I copy a Glimmerpost and immediately kick myself for not Vesuva-ing his Ancient Tomb which would have allowed me to cast Titan a turn before I actually did, while having the damage prevented by Chasm. I also let go of the Chasm after two turns which proves to be bad as he has Dismember + Jitte counters for the Titan. I fumble around with Top but find nothing, though I did have the mana for Zenith->Elderscale Wurm which would have won the game.
Round 13: 0-2 vs. B/R Reanimator (Todd Anderson)
Game 1: Having seen some of the coverage the previous evening, I know what he is playing and am not pleased. I mulligan to Crop Rotation and get to Bog his graveyard after he reanimates Griselbrand and discards 11 cards. I don't find a Karakas or Swords though, and effectively lose when he reanimates Tidespout Tyrant. Mental invective is spouted.
SB: +3 Leyline, +2 RiP
Game 2: I mulligan to a 4 with Leyline, Top, and a land and hope to find Rest in Peace. I don't, and he has T2 Animate Dead on Tidespout with double Lotus Petal to bounce my lands. I still don't find a Swords for the Tidespout.
Round 14: 2-1 vs. Merfolk (Cassidy Delcourt)
Game 1: I play some lands, resolve Crop Rotation for Cavern, and proceed to drop 2 Primeval Titans over the next two turns with a third in hand. Ulamog gets Forced, but Emrakul tears the aeons and her board.
SB: +2 Grip, +2 Ghostly Prison, -2 Warping Wail, -1 Bog, -1 Crop Rotation
Game 2: I keep a slow hand that I really should have mulliganed. She plays Back to Basics and I opt not to cast anything so that I can topdeck Grip, Rec Sage, or Zenith. I don't and get run over by merfolk.
Game 3: Basically the same as Game 1. Steamrolling opponents is fun.
Round 15: 2-1 vs. Miracles (Matthew Tickal)
Technically this was an ID into top 64, but we played for fun and I saw a Miracles build that I hadn't seen before so I'm including it here.
Game 1: I lead with a Forest, expecting to Crop Rotate it. He plays an Island and passes, from which I decided he is playing Miracles. This conclusion was confirmed by the groan upon seeing the Forest become a Cloudpost. This Miracles player, however, plays Wastelands which buys him some time. Emrakul eventually cleans up anyway.
SB: +2 Grip, +1 Ghostly Prison, -1 Bog, -2 Crop Rotation
Game 2: I expected him to play Mentors, which he did not, but did not expect Wasteland + Crucible, which he did. He Forces my GSZ for Rec Sage and I don't topdeck a Grip for the Crucible before I have too few lands to cast it.
-1 Prison, -1 TKS, -1 Map, +2 Rest in Peace, +1 Bog
Game 3: He never finds a Wasteland, and although Clique + Karakas slows me down I eventually get Titans through Caverns for the win. It turns out that Eye + TKS is very good against Terminus.
Observations
1) Ghostly Prison leaves much to be desired. While it severely hampered my first U/R Delver opponent, I never managed to both resolve it and have it be more than a mere nuisance in any subsequent match. My eldrazi opponent did TKS it away, which I suppose indicates that it has some utility in that matchup. I think I would prefer actual removal (Blessed Alliance, more StP, maybe even Clip Wings) in its place but I'll test it some more.
2) Neither Dawnstrider nor Elderscale Wurm made an appearance, so no experimental results for those.
3) Naturally, the first tournament in which I play Rest in Peace over Surgical Extraction is the tournament in which I play against B/R Reanimator. So I continue to waffle on the choice between the two. I'm not sure how necessary RiP is against Lands: I've reached the conclusion that I can beat all but the best Lands players by being smart with Bog and Karakas, but my local meta has multiple strong Lands players. RiP played no role in my win over Shardless, which is the other matchup in which I'd want it, but did stop Surgicals from my 4c Delver opponent. Perhaps a coin flip is in order.
4) I return to my prior opinion that 3 TKS is too many. It isn't particularly good on defense as any attacker + Bolt kills it, and isn't particularly necessary in any given matchup other than perhaps Omnitell. I do like having at least 2 in order to tutor them up with Eye and snag Prices while allowing for one to get countered.
5) Contrary to previous experience, Candelabra was not necessary to fight new Thalia from D&T. Granted, in the times when she appeared I was firing on all cylinders anyway.
6) StP was amazing, and I'd like to play a 3rd copy. Having more answers (and nonland answers) to Marit Lage makes the Lands matchup feel like a breeze despite the absence of Pithing Needle.
7) 4 Forests seems like the right number to get maximum value out of Veteran Explorer even after drawing or being forced to fetch basics. Only once (against Nic Fit after he had already sacked an Explorer) did I get fewer than 2 basics from my Explorer.
8) Explorer was excellent against slow decks and eldrazi. I took it out against U/R Delver but it might be correct to keep it in since one needs to ramp quickly in that matchup.
9) Maindeck Reclamation Sage was OK but not great, and its best moments were in sideboarded games. I didn't face many Chalice decks though and I think having the extra sideboard slot helps.
10) The Delver matchup needs work. My plan was to tax their mana with Tabernacle + Prison + Trinisphere but after the first match decided that Trinisphere was not that good, and the full taxing plan only worked against one of my Delver opponents because it takes three turns to set up.
11) Khalni Garden > Dryad Arbor still, though on a couple of occasions it would have been nice to be able to Zenith for 0 meaningfully.
Thanks for reading, and I welcome any thoughts or questions you have.