GP houston advice

I'm going to GP Houston this week, I was wondering if I could get some advice on what would be a good choice to play. To be honest, I haven't play much of standard since oath of gatewatch came out. I have 4 color rally built, but I'm worried I'll lose in mirror matches where my opponent has had much more time with the deck. This will be my second GP, also if anyone would like to playtest on mtgo or cocktratrice that'd be cool too.