Your cage heat should be around 80 degrees, 75 the lowest at night. I've never used flexwatt on an aquarium, but I am figuring that it might get a little hot. Flexwatt transfers heat much fater than the heat pads. As you expand, just a word of advice, snake racks with bins are a much better bet then tanks or enclosures in my opinion. Throw on a herpstat and you pretty much have a perfect environment for basking, ambient heat and humidity. I did the glass aquarium and it was just too much work getting everything right.
Good luck,
Flexwatt doesn't transfer heat any better, it simply gets way hotter. Any under tank heat source needs to be regulated by a thermostat so it really doesn't matter.
Thank you all for your help! I will definitely be purchasing a spyderrobotics thermostat! want to make the animal as comfortable as possible, might as well pay a little extra!