The pvc is 1/4 inch thick. It is very sturdy and very well made. I have Jim assemble them for me since I also live in MI and am able to pick them up, but you can assemble them yourself to save on shipping. They go together very easily. I bought my 3x2x2 preassembled for $340 and it came with light, perches, and RHP. Couldn't beat that!

I hope you don't mean to keep multiple species of snakes together in one cage. Snakes are not social animals and do not do well living in groups. They should each be kept in their own seperate enclosure.

What size is your ball in now? A hiding BP is a happy BP and if yours is generally only exploring at night, that's normal. I wouldn't try to fix something that isn't broken. Just because he's exploring a bit at night does not mean he should have a bigger cage. This larger cage you're looking at setting up might be better suited to a different species altogether. Have you considered a rainbow boa or a colubrid species such as a bull snake or a corn snake? One of these might work better....