I use the Herpstat 4 from spyder robotics and love it. All of there Products look great. I would use 11 inch flexwatt. You can purchase 11 inch flexwatt in just about any length at reptile basics. You can even have them wire it up for you. The cages I have are made from 1/2 inch thick controlled density PVC plastic and the 11 inch flexwatt on the hot side combined with a RHP to regulate the ambient temp works great. I use 2 thurmostat channels per enclosure. Some people would consider this overkill but then again I am OCD LOL.
Where did u get ur plastic? I have thought about making bottom back and top solid black and the sides front clear acrylic.... also my buddy has a controller from spider that controls 2 zones and humidity... what device could u use for the humidity?