Remove the UTH from the side, put it on the bottom
Have the thermostat sensor sit between the UTH and the glass (so it doesn't get peed on)
Have that one set to 90 degrees
Duplicate the same setup on the right side of the tank, but set to 80 degrees (or 92/82 because of the substrate, liner and glass that could cause heat loss before it reaches his belly)
Remove the heat lamp if the temperature is okay
Relax
Anything I missed?
Sounds like a plan. Also, you might have to play around with what your Tstat is set to. Mines set to 98, which gives me a 91 reading on the substrate.