I agree with using the larger UTH for your warm end. This past winter I had to use an electric space heater for my snake room. This year I will probably try to pick up a couple of the oil filled ones. I didn't really trust the built in thermostats, so I set up a Johnson for the heater. Since the heat rises, I set the heater on the floor next to the tubs and put the t-stat probe up next to my highest tub and set it for 82F. I also kept the ceiling fan on "low" speed to help circulate it a bit...