Switching to tubs. How do I regulate the heat?

[Spaniard]

I have had my girls up to 800 grams in a 15 qt, no hide, eating like monsters and doing great. Then they got moved to a 28 and are still eating like monsters.

Same thing here; I have some 800g snakes in 15qt tubs because they would not eat in the 32qt and they're doing just fine. What works for one snake doesn't always work for another. If you want to attempt the 32qt that is fine but be prepared to try a smaller enclosure if your ball doesn't eat. I would personally stick to the 15qt tub and switch to the 32qt later on. The only thing you would have to spend extra on is the 32 qt tub; you could reuse all your other supplies. You'll probably need two UTHs for the 32qt tub if you choose to go that route.