That's correct for a 4x2x1, I was figuring 4x2x2. I don't have an adult ball, so I wasn't sure about its requirements. Mine is still in a 15.

So just so I don't mix up further, I'm reading that you have an RTB in a 4x2x1 with climbing branches and a heat lamp?

My RTB doesn't use his hides very often, but will burrow and climb on his branches. He's the only one I have equipped with a heat lamp
I use 4x2x1 cages
When they are fully grown, hides become difficult to come by that will fit them
RTB forums are a good resource for information. A lot of guys on there use cat litter pans for hides. I suggest the OP should check them out. They have many ideas for large hides, cage requirements and all that.