I figured the flexwatt would be better, and I am getting a thermostat before I put anything in there. I know the dimensions seem big...but it's not much bigger than my 20 long gallon glass tank I have, maybe a little taller and two inches longer, and I have a 6 month old male in that now and he's fine. I am putting black Con-tact paper on the two sides and back, as I do with my glass tank. It's gonna be at least a month before I get anymore snakes, so I have time to change things around if needed.