I would go 6'x2'x12" for a boa then you can have 3'x2'x12" for Ball Pythons on the top, Would be sick.
that would be nice but it wont fit in my room for now and ill be here for a while, when i get my own place again im gonna build a 6'x3'x3' cage for my boa
im painting it and using a clear coat sealer paint i have to let dry and ventilate for about a week from vapors. but i seal all the joint with water based adhesive/chaulking/sealer