Be careful with and UTH if it's not on a thermostat. They can create hot spots on the floor of the enclosure. Get a IR Temp Gun to check the floor temp in different spots where the UTH sits.

Also, if you are using a glass tank with a screen top, you will play heck with trying to keep the humidity right. Trust me, I played that game and thought I would be able to keep it right, but I ended up buying one of these:

http://www.reptilebasics.com/Mini-Cage-p-16232.html

Keeps the humidity where I need it, and my juvenile BP actually seems more at ease in this cage than he was in his larger 20gl tank.