Need help on heat setup for new cage

Hey guys, new to the forum. I just bought a new plastic cage from constrictorsnw.com (30x24x12), along with a 40w radiant heat panel and i want to get a new UTH from Ultratherm, i was thinking either the 11x23 or the 11x29. Not sure of which to get, any opinions there? It can get pretty cold in my room where i keep my snakes (65 in the winter). My main question that ive prob been overthinking for too long is how would you guys set up the heat to make it most efficient for my BP. For example, should i put the UTH towards the back horizontally across the cage under the heat panel? under the hideouts? Any help would be greatly appreciated.

I would put the heat pad under the cage covering appoximately 1/3 to 1/2 of the bottom with one hide over the heat and one hide off the heat. Make sure you have a good thermometer for both the warm side and the cool side of the tank and get a good thermostat to regulate the temperature because the temp in your room will probably not be consistent.

sounds like a plan, yeah i have some thermometers and hydrometers w/ a thermostat ready to go, thanks for the reply and relieving some of my confusion