Good on the thermostat.
However, make sure you checking temps with a IR temp gun and inside hides as well. I shoot for 87-89F for my ball python, but have a few spots about 90F and a few about 86F. Inside her warm hide it's about 89-90F.
Remember, the ground temps are what matters, and that's what you should measure. The placement of the thermostat probe and its reading can be different from the ground temps.
Also, if using a substrate, remember, BP's will borough, so the hottest temp is what you measure, even if it's on the bottom of the tank (if you use a heat pad for example) .
Good luck and keep us posted.