I just built a custom enclosure for my ball and I'm trying to figure out the best way to provide belly heat. The enclosure is all wood except for the plexiglass doors on the front. The base is 3/4 MDF and the rest is 1/2 plywood. Is it safe to put a small UTH under the substrate? Would it be better to go with the intellitempt or an adjustable heat mat? Someone please give me an idea!