Boas and balls are waaaay different
My boas have an aspen play area (they like to hide sometimes) and I use kraft paper as the substrate throughout the cage.
My boas really like to climb and that is why I am getting them permanent cages with height as well as length
Bcc's are known to have digestive issues, especially when young, but Bci's are pretty sturdy little snakes.
Can't speak to UTH questions (or tubs) as I house my boas in RBI cages and use RHP's for heat