Yeah 70's too low for the cool side. Get it over 75 to decrease the chances of respiratory infections.
1 UTH would work just fine with a thermostat set @ 89-93 degrees. The reason your temps are so high's because you have so many heat sources and that combined with naturally produces FL heat can be a bit much. BP do just fine with belly heat. Regulate the hot side and the cool side should be controlled by the temperature of your house. To keep ambient temps up I use a space heater, but I also use a single tub rack and not a glass tank so keeping temps and humidity right are not a problem.
Before I got my BP reading this really helped.
http://ball-pythons.net/forums/showt...%20foil%20tape