First off welcome to the forums, happy to have you!
You'll get some differences of opinion on this for sure and what works for one person/snake may not work for you. That being said, I kept my BP in a 40 gallon for almost the whole first year of his life. A lot of clutter, multiple hides, plenty of stuff to crawl through so he didn't have to be out in the open if he didn't want to be, and he did great. I did keep my warm side a few degrees higher than yours, right around 85 was my sweet spot and relatively easy to maintain in a glass enclosure.
I would be careful about moving him back and forth between enclosures, you don't want to cause unnecessary stress, and realistically each time you move him you should go back to the "no-handling until he eats for you 3 times consecutively" rule. So figure out what you want to do either based on our advice or your own research and stick with it.