40w che enough?

85F on the cool side seems a bit high to me. I keep all my cool sides around 78F and its weird but all my girls spend most of their time on the cool sides lol. They are called tropical snakes but they don't act very tropical haha.

I had a 60w, I think, and it did okay for a 24x24x14 plastic enclosure but it was maxed out. I'd think 100-150 would be plenty.