Super quick update! After a week of running and about 6 days with no temp or humidity fluctuations, I moved the BP into the T10 today. It was still dark when I did it, so he checked it out a little but then settled into a hide as the sun came up. So far so good, Friday is feed day so fingers crossed we don't have any issues. Thanks for the input from everyone!
As far as his old enclosure, I spent my lunch scrubbing the hard water stains off with some water mixed with vinegar, and once that airs out for a day or two I'm going to disinfect and set it back up. My plan is to move my leopard gecko in sometime next week once I make sure all the temps are good to go. His old 20 gallon long will go to the spotted python once he's done with quarantine, 30 days down 60 to go!