I very much agree that too large an enclosure can be a serious problem, both from my own experience and that of people I've sold offspring to. But cold and dry are problems, too (I'm in Wisconsin, so I sympathize with you). Can't win sometimes.

AP cages can come with a center divider (so a T8 can be two 2 x 2 x 1' enclosures) that is removable. Do know that their lead times are months (sometimes like 6 or 8) so order early.

Personally, when I can I like to hit the animal itself with the temp gun (avoid the eyes!) to get the most accurate info, but that probe in the hide is a great idea.