Leading up to the Pro Tour, my team was one of the last I knew of to confirm who would play which format. We were pretty sure Matt Nass would play KCI in Modern--even as new developments like Spirits and R/B Dredgevine showed up that looked a little scary for KCI, it still felt like the best we could do, especially since it let us focus on other formats. Sam Pardee was testing Legacy, and Matt spent most of his time helping with Legacy since he didn't think he had much work to do on Modern. I played a bit of Legacy myself to see if I wanted to advocate for Lands or Zombies, but I mostly decided I'd let them decide if they felt like we should be playing a Brainstorm deck, and I'd let Sam play it if that's what they wanted. (For the record, I think Brainstorm in Legacy is the most overrated card in any format--it's great, but a huge portion of pros think you shouldn't consider any deck without it, which I think is far from true, but I also knew that I wouldn't be able to be sure about my choice, so I wanted to err toward trusting them.)
A couple weeks before the Pro Tour, I started really focusing on Standard. The Sai/Outcome deck looked great and showed a lot of potential, so I spent almost all of my time working on that. Before GP Minneapolis, I packed my luggage for a week in Minneapolis and the only Standard cards I brought with me were most of the cards I was considering for Sai/Outcome and my R/B deck from Nationals.