Thanks to all for their help.
I've continued to see awful prices and routings for next-day or even day after flights. However, I've found that I can book Tuesday at 12:01 AM for Thursday, and hold until 11:59PM local time Wednesdsay. Thus I can effectively book three days ahead. It's Thursday evening now and we won today, so I cancelled my Friday flight, I have one on hold for Saturday, and after midnight I'll book for Sunday. The tournament ends Sunday so I only have at most two more iterations of this, but it's not that taxing.