New terrarium, How to heat?

Well, I've finished building my new terrarium. Now I'm trying to figure out which type of heating I should use. According to the T-Rex info they are usable inside terrariums, does anyone have any experience with using them under the substrate in a terrarium? Any other recommendations as to which heating system to use?
Here's some pictures of the terrarium, and my daughter as well:

Well the best thing I can figure is that if you put a UTH in there, place a tile over it, they disperse the heat well and in addition your snake won't be able to get right on it and you shouldn't then have to worry about urine or water spilling and causing an accident.

Big problem I see with that is that the exo-terra heat mats available in town all say not to use with wooden terrariums, and that they need air circulation. That's why I'm looking at the T-Rex Cobra mats.

Well I use tile in my gecko cages over the UTH but in the wooden one I have holes drilled into the bottom of the viv for air circulation.

Edit: and the UTH is zoomed.

I'm in the UK and quite a lot of people over here use "ultratherm" heat mats inside melamine vivs. Some people recommend placing a tile or piece of plexi glass over the pad, under the substrate, as that protects the mat and distributes the heat better.
These mats dont get extremely hot to the touch, but they heat anything they are in contact with to quite a high temp, but using a thermostat will keep the temp correct

I saw a link on here for an American site that sells them, oh here it is...

http://www.beanfarm.com/store/agora...E7nB7&product=Heating&user4=Undertank Heaters

and this is the thread that it came from

http://cornsnakes.com/forums/showthread.php?t=47356&highlight=ultratherm

Hope that helps, best wishes,