I don't have experience with the large ones, but I do use 1 24"x18"x12" and 2 18"x18"x12" for young boas. I had glass cut for the top, then I drilled and installed a radiant heat panel (28 watt Reptile Basics) wrapped the sides and back with reflectix insulation. They work like a charm with this set up.
-----
Reptiles Make The World Go Round.
