you have a thermoSTAT in your cage? are you sure that you don't mean a thermoMETER?
any UTH can be regulated by a thermostat, in fact they ALL MUST be regulated by a thermostat. UTH's can easily get hot enough to kill a snake if they aren't being regulated.
Here are 2 good thermostats:
Budget: http://www.amazon.com/Hydrofarm-MTPR.../dp/B000NZZG3S
High Quality: http://spyderrobotics.com/home/products.html
Stay away from the thermostats sold in pet stores they are overpriced junk.
Here is a thread with more info: http://ball-pythons.net/forums/showt...t-Thermometers
Switching between 2 different heat sources probably isn't the best idea. you want your cage to be as consistent as possible (and in the right temperature zones: 88-92 F on the hot side and 78-82 F on the cool side)