Hey hun!
So I'm not a snake owner - YET - but I've done a lot of reading ... both on this forum and in the book.
I've read all the comments to make sure I'm not giving you advice somebody else (somebody MUCH more qualified to give advice) hasn't already given, but some things I'd like to point out because I'm afraid they might have been missed by you (no offense <3)
The regular lamp dimmers you can get at any home improvement store like Lowes or Home depot will cost somewhere <$5. They have their own little outlet and you can plug the Heat pad right into them. No need to wire anything, it's very easy
You can purchase a probe thermometer really almost anywhere (I bought mine off Amazon, they were much cheaper than Petsmart) and use a hot glue gun to glue the probe directly on the glass above the heat pad. That way the probe doesn't come loose if the snake happens to burrow down into the aspen.
He might not WANT to burrow down because it's too hot for him.
Also, as said before: The reason he doesn't come out of his rock at all is probably because he doesn't have another hide to go into. I've read that snakes choose safety over health, so he'd much rather "cook" than be out in the open if he doesn't feel safe there.
Since you are worried about space in your tank you might need to exchange the water dish - albeit very nice - with a plastic dog dish. I've seen people cut out a semi-circle on the bottom of those and sand down the edges, or I've seen people posting pictures of plastic dishes that already have holes on the side. There you'd have a hide and a waterdish big enough for him to soak in and drink from. And they are easy as pie to clean. I've attached some pix.
Tap water seems to be an issue if the city is putting too much chlorine in it. I for example would have a big problem, because our city water is just ikky. We already own water filters we use for ourselves, but you might want to look into getting a small one to filter the snake's water. Or, you can just use bottled drinking water. No Distilled water, as it's missing important minerals.
In Don Sonderberg's book i've read that more new snake owners were worried that the snake wasn't drinking, because it wasn't coming out of it's hide noticable to them. He said that placing the waterdish directly next to the outer wall will kinda "force" them to slither through as they trace their boundaries and they pick up some water that way. Though - thinking about it - I think your picture already showed the waterdish on the front side, didn't it?
Hope that helps a bit. Nothing anybody else hasn't said yet.
I'd also like to jump the band wagon and pad your shoulder for rescuing this fella. Job well done! You seem like a very caring person and I'm sure he'll thrive in your home ;-)
im sure they are fine!
