I have a feeling Mac will give me a hard time to go in that box, he's the type of tort to go to his little corner, dig down and be happy with that. At first I would put him under the log hide every night and he would stay there sometimes but never go into the hide on his own at night time. He only uses that hide when the sun is beaming and he wants shelter. How would you shrink that box in size? Do they sell smaller mats? Smaller radiating heat things?
Do you feel Mac would benefit from this more than me just setting up an indoor temp box for him? Where's he's at, I don't have power, I would have to run an extension cord from my outlet against the house to him, that might be a problem.
1. You never know. Sometimes they dive right in on night one, and other times they fight you on it for months.
2. Shrink it? You'd just cut the plywood pieces smaller during assembly.
3. Yes on the smaller mats. They sell a 24x24 that would work well in a 24x26" box. Kind of big for one russian, but this will allow him to be on or off the pad while in his box. They sell a 21x21" RHP, if you need it.
4. I think in your climate an outdoor box will work better than a small indoor set up. This is highly debatable. Either way can work for you.
5. I've used lots of extension cords. It can be done safely and work well.