This deck is a riot! I remember play testing this when you were first developing it. I loved it then and love now! I just threw this up on my goldfishing app and first turn I had a Chalice set at 1, a Salvage Titan and 2x Frogmites in play. It's explosive no doubt! Great ingenuity! Sagas look good here and the Echos really add a lot! It seems like it tends to stall a bit more than it did (if I'm remembering playing your older builds correctly) but that is circumvented with the Echos. Diamond Lions are great here!
I was thinking about the fact that Mystic Forge lets you peek at the top card of your library and wondered if
Codex Shredder wouldn't suck here. It only cost one and Shredder could help assist nixing the top card of your library when you stall out with Mystic Forge.
Another thought is
Lantern of Insight. It's main ability (looking at the top card of your library) isn't super great here but it's secondary ability which lets you shuffle when you stall out doesn't suck at all.
Both together do awesome shit. Not only for helping you go off but also for nixing your opponent's Terminus or other major threat your opponent might come up with.
The deck is amazing as it is, so I wouldn't want to change to much, but those options might be worth looking into.
Have you had a chance to test it against the gauntlet?