For reference, the lists Luis and I used can be found
here. With regards to how we came to those lists, I can't comment completely on Luis's. I was asleep on the floor before he and Gerry finished brewing. The shell I used started off with Jimmy McCarthy's list from the ICBM open (held the weekend before) in Chicago. I read the few bits of discussion regarding the deck and various card choices, like Sphinx of the Steel Wind, Jace, Skeletal Scrying, etc and made changes from there.
I knew that I was playing Time Vault and Voltaic Key. The combination is simply the best option right now. The tournament was going to be sanctioned which meant no proxies. A lack on proxies indicated that there would likely be more fish and ichorid than I would normally expect. Expecting more ichorid in a non-proxy metagame may seem odd, but obtaining four bazaars seemed a bit easier than anything else given the task.
With the expectation of more fish, some of the variable slots were dedicated to creatures, like Fire/Ice and Sower of Temptation. Gauging the effectiveness those cards had is tough because the sample size was so small. I played in the prelim tournament on Saturday (losing in the finals to BUG fish) and the main tournament on Sunday (spliting in the finals). When everything is tallied, I played out a total of twelve rounds (going 9-3) losing to Tezerret, BUG fish, and 5-c stax. I can't really say whether Fire/Ice or Sower of Temptation was definately the _right_ call. They had their uses, but they might have been better as something else.
Duress vs. Thoughtseize was another difficult point to consider. I played three Duress/one Thoughtseize for both tournaments. I'm not sure on what plan is best for combating BUG fish postboard. Basically, what it comes down to in my mind is if you want Thoughtseize or Mana Drain and in what numbers. Additionally, if you want Thoughtseize, do you want a basic Swamp? Using a manabase immune to Wasteland is huge. At the time of the tournament, I didn't think too hard about Duress/Thoughtseize. I just defaulted to Duress.
For a draw engine, there was really only one question: Dark Confidant or no? I knew for sure that I didn't want to play Mystic Remora, Thoughtcast, or Intuition/AK. I would only play Thoughtcast in Japan. There are roughly 8.5 Null Rods in the entire country. There would be too many creatures to make Mystic Remora good enough. I figured that Night's Whisper would be the best non-Dark Confidant option because it was cheap and not reliant on what my opponent was/n't playing. In terms of power-level, it's a bit lacking. It provides the same raw advantage that Thirst for Knowledge provides (technically), but is leagues worse. I didn't want to run Dark Confidant for similar reasons to Thoughtcast and Mystic Remora. With a higher saturation of fish comes more sideboard cards dedicated to creatures. Like Mystic Remora, I didn't want to have my draw engine colded by a bunch of Swords to Plowshares.
Tinker was given some thought. Inkwell Leviathan vs. Darksteel Colossus, vs. Sphinx of the Steel Wind. The choice came down to Inkwell or DSC. Alll of the good versions of blue decks run Hurykl's Recall or at least soem way to deal with Inkwell. I would beat the bad versions regardless of what I ran. Since the majority of people will be prepared for Inkwell, I'd rather run DSC since it ends the game so much more quickly. Against aggro, Sphinx is okay. The turn it comes out, they can't really attack you and benefit. That said, it takes four turns to kill them opposed to two with DSC. Depending on what their board looks like, those extra two turns can mean you losing. Sure, Sphinx and Inkwell are blue and can be pitched to Force of Will, but I don't really want to do that. In a matchup where you really want to Tinker your monster into play, you really don't want to exile him. That makes your gameplan so much weaker, having to battle through their Null Rods and Wastelands before they kill you with their terrible creatures.
I was happy with the sideboard for the most part. Leylines were awesome. I'm still toying around with sideboard slots for fish. Playing a bunchof smothers might just be better since they're cheaper to cast. Sower is expensive and sometimes you aren't able to cast it.