The Zilla will work ok but the probe is in the wrong place. If it's in the tank your BP can (and will) move it off of the UTH, pee on it, etc. which will then let the UTH overheat. The probe needs to go outside of the tank sandwiched in between the UTH and the bottom of the tank. I would start with the thermostat at 90*F and then use an temperature gun or IR thermometer like http://www.amazon.com/Zoo-Med-ReptiT...1367176&sr=8-2 to measure the temperature of the glass on the bottom of the tank. Adjust the thermostat up or down as needed so the glass temperature is around 90-92*F.

WalMart sells an inexpensive digital thermometer/hygrometer so you can monitor the cool side:
http://www.walmart.com/ip/AcuRite-Di...nitor/16888914