guys I need help, rack system or vision cages?

so I have 3 ball pythons, soon to be 4. I'm also getting some other snakes in the next year. I'm currently housing each of my 3 snakes in their own 40 gallon terrarium. obviously this isn't going to work forever. I'm completely out of room. I obviously need to either get them into a rack system, vision cages, or something a little more appropriate. my main concern is my snakes health, being happy, and being comfortable. I've seen pretty much everybody use racks, but I just feel like they're a little to confined... vision cages seem like they would be a little more comfortable. although I know a lot about snakes, I don't know so much about all the different types of housing choices.
and if I were to get them racks, do any of you know where I could get a rack with the most tub space possible? thanks in advance!

I like to advocate for more space whenever possible. Racks are great for breeders with big collections, but for a handful of snakes I'd go for the more spacious enclosures. It gives you more options to add enrichment if you want to - a branch or two, an extra hide, fake plants and other visual barriers, etc.

If you decide on a rack, you could always look into making something custom to fit your preferred tub size.

If your room temperature is anywhere above 75 a rack will work great. I would get a small rack that holds 4 or 5 of the Iris CB70 tubs. Most Ball Pythons will thrive in that setup. If your room is cooler than that you can go with a PVC enclosure.