http://www.starcitygames.com/decks/131272
Got 11th in an SCG Classic running 4/4 Welder/Engineer split feat 4 Astrolabes as Welder food + fixing. Beat 4c Control, Miricles, Grixis Delver, Turbo Depths, Stoneblade, and Infect. Lost to Lands (with a spicy sideboard) and UR Delver. Managed to dodge Chalice decks and SnS, and looking around it seemed like Post was everywhere.
I'm big on Engineer. It was gas and I felt like it was allowing me to keep threatening to combo way more than before we had it. Recruiting it to get a Grindstone was 👌, and with the full 8 Welders the yard was pretty live. I didnt see any Surgicals all day, so I not sure if they're just low in the meta right now or I got lucky; only gravehate I saw was New Ashiok out of the Stoneblade or Miricles list.
4 Bolts in the side is very correct imo, especially for Arcanist which just runs a train on whoever's sitting across from it.
Changes I would have liked to make is go back to 20 lands with +1 Great Furnace (felt like I had very little mana all day) and +1 ETutor (2 felt like too few), not sure what I would want to take out. With 4 Petals, 4 Labes, and 3 Grindstones, I feel like I had just enough cheap artifacts to get the Welders started, I dont know if you should go lower if you're running the full 8.