Welcome fellow Texan! I would say you could go either way with a tank it a tub. The main thing is trial and error before you get your snake. Check humidity and temps and see how they fluctuate so you can change substrate, cover part or the tank, etc. to get desires humidity. As far as temps, my house stays pretty chilly too, but I have my snakes in one of the bedrooms with the vent turned down so it doesn't get so chilly in summer. Good luck, I know even with your unique situation you will figure it out