From @evouga 's great work in the SMIP thread:

Realistically though, you wouldn't keep a 7 card hand since you don't put cards on the bottom, so if your only method of putting of putting a Sphinx on the bottom is the London mulligan you are 60% to find it? With Powders (I think)? Which is awkward since you can't powder away more than 2 Chills.

And this equation assumes you are only mulliganing to Sphinx, not a generally acceptable Magic hand that also has lands and spells.

So can I just run Oath shell with 4 creeping chill, then have Magister Sphinx as my only creature, powder/mull to get sphinx to bottom, then activate oath one time??

I wondered the same thing when creeping chill was spoiled in the single card thread, but getting Sphinx to the bottom was tough. Now..

Perhaps the probability of a single Sphinx in the opening 7 that you can bury through the mull is still too high.

@prn Awesome to hear UW Eldrazi worked for you! What did your manabase look like? When I tested UW, I swapped my 4 Plains for 4 Adarkar Wastes and had huge issues casting Lavinia. Some lists are also playing Tundra, and while that would definitely make casting your blue cards a lot easier, I don't see a way of fitting Tundras into the list that I like.

@gRR Kataki's issue against Shops is that he can be Ballista'd really easily - you kinda need Kataki and either Null Rod or Revoker to protect him. I still like Kataki, but Flux is definitely much stronger if you can resolve it. Tabernacle is a great idea, though - would love to hear how it works for you.

@prn I'm not convinced about adding Lavinia to White Eldrazi; we are already punishing our opponents with Thalias, Thorn and Glowriders with the mono-white versión, and adding Adarkar Wastes makes us more vulnerable to Wastelands.

I prefer Kataki instead of Energy Flux because it's a creature, so we can play it out of Cavern of Souls, costs 1 less, is unaffected by Thalia/Thorn/Glowrider, and does not compromise our manabase. Sure, its effect is half as broken as Energy Flux's effect, but I prefer to play safer.

The more I think about it, the more I'm liking a couple Tabernacles in the sideboard. I'll test them next tournament instead of Ratchet Bombs.