This is my setup up so far. I know everything is big for them, but this was my first attempt at tubs. They BPs seem happy with it and not stressed, so I didnt bother to make everything smaller.

My thermostat probe is taped with aluminun tape directly in the heat tape. You can see the probe in between the tubs. I use an accurite probe to find a stable temp for them from the heat-tape/thermostat.

I was using newspaper before, but it was a pain to change the paper and clean the tub everytime they pee or poop.

Im trying aspen now, but it has it's cons too. the main con I worry about is when the snakes are eating, the aspen get stuck in their mouth and unless I help them remove it, it takes them a while to "spit it out". It REALY get stuck in their mouth. The second reason, it is much harder to maintain a stable temperature. Third, well, it's just not free . I think I am going back to newspaper soon or some form of paper. Any tips anyone?