I keep mine on the hot around 90-95ish with egg falts and paper towel rolls to they climb up if they find it to hot. I did turn it one time to above 100 and notice a couple die offs. Then turned it back down and haven't had a dead one in about 2 months. Also have a cool side only heat one side of you bin/cage.
it depends on wat u want. If u want them to breed really fast the lower 90's or upper 80's work and if u want them to slow down around lower 80's or upper 70's
I have mine at about 80