Hi, an welcome to BP. Now, the grow tents I use on the farm won't work for any of my BC's. Your snake will try every corner, push on the walls trying to collapse them an find the zipper. Yes, the Boa will open a zipper. You can do a test by putting your snake in a popup tent. It might take a bit but the snake will try to borrow at the base of the zipper. Then bingo the zipper moves just enough. Hook an loop might work better.
How would you keep liquid from leaking out?
Watch craigslist an your local freecycle for large free tanks an cages. I have ten 100-175 gallon fish tanks behind my shop found that way. You can use a free tank as is or take it apart to make a custom enclosure. If your good at woodwork or have a friend. Make an addition to your enclosure.
Good luck!