I've been looking for a way to transition the Control Slaver strategy I usually pilot in this format to something with 4 copies of Gifts Ungiven, and I ended up piloting the following list to a split in the finals of a smallish (11 people) tournament earlier today.

2 Goblin Welder
1 Sphinx of the Steel Wind
3 Dack Fayden
3 Mental Misstep
3 Mana Drain
4 Force of Will
1 Brainstorm
1 Ponder
1 Ancestral Recall
2 Dig Through Time
1 Treasure Cruise
4 Gifts Ungiven
1 Yawgmoth’s Will
1 Tinker
1 Recoup
1 Voltaic Key
1 Time Vault
1 Time Walk
1 Sensei’s Divining Top
1 Demonic Tutor
1 Mystical Tutor
1 Vampiric Tutor
1 Mox Pearl
1 Mox Sapphire
1 Mox Jet
1 Mox Ruby
1 Mox Emerald
1 Black Lotus
1 Sol Ring
1 Mana Crypt
1 Mana Vault
3 Underground Sea
2 Volcanic Island
1 Island
4 Polluted Delta
2 Misty Rainforest
1 Academy Ruins
1 Library of Alexandria
1 Strip Mine

Sideboard
1 Slice and Dice
1 Flusterstorm
1 Misdirection
1 Pyroblast
1 Red Elemental Blast
2 Goblin Bombardment
3 Grafdigger’s Cage
1 Yixlid Jailer
1 Hurkyl’s Recall
3 Ingot Chewer

Matchups were as follows:
Shops: 2-1
Mono-red Storm (AKA the bye): 2-1 (I'll admit that he caught me off guard in game 1 when I had tapped out for Dack with a hand of Gifts and Time vault when he stormed for 9 and cast Ignite Memories on me...)
Shops: 0-2
Cobra Gifts: 2-0
Oath: 2-0
Oath: 2-1
Shops: Split

I was pretty happy with the deck overall. I'd like to maybe have a Pyroblast back in the maindeck as well as something like Hurkyl's Recall or Misdirection to help out in the BUG matchups where Abrupt Decay can put a serious damper on my combo turn. Misdirection is probably the right call to move in, though I'm not really sure to cut for it. I also think Snapcaster Mage definitely needs to be in the deck, as sometimes having only Recoup for that effect can be very limiting.

The manabase also needs a bit of work, as I don't actually own any copies of Scalding Tarn. If I end up playing something like this again, I'd probably make the following changes:

MD:
-2 Misty Rainforest
-2 Polluted Delta
-2 ???
+4 Scalding Tarn
+1 Misdirection
+1 Snapcaster Mage

SB:
-1 Misdirection
+1 Mountain
Other changes dependent on metagame.

The metagame where I play has a ton of Oath players and very few Dredge players, so my sideboard choices reflect that. It might be possible that the supplementary countermagic in my board is unnecessary, but I really like the flexibility that it gives to Gifts.

I am still a relatively unexperienced Vintage player, so any comments on the list or suggestions for changes would be greatly appreciated.

Thanks again for the basis for the list I ended up running at this Rich! It was a blast trying to navigate the mirror, and I hope to improve for our future matches.