Just got ball pythons as well and my outside ambient temps are around 72-76F, I have two rows of holes on each side of the tub. Inside the tub the temps are 75-80F on the cool side and anywhere from 88-91F on the hot side. I would just set up the tub and see what needs to be tweaked (more holes, less holes, raise/lower tstat setting etc.)
-Jone