Just wanted to circle back on this months later, I’m no expert on ball pythons, that’s for sure as a whole, but I do LOVE myself some varied enclosures. I have tub setups, glass aquarium setups, wooden vivariums, and my other homemade acrylic cages along with my sterilite bin racks. Since I have such a varied amount of enclosures I just wanted to chime in on the situation since I feel like regarding advice this is the one and only place I have space to speak on since I build and manage most of my enclosures, and the ones I don’t are generally modified to be more fit for a snake so I have a bit of experience regarding what I feel best is for at least my snakes and what materials, sizes, and formats I go with.
Personally I’d say there’s no right answer, for a 20 gallon you can squeak by with one with juveniles, in my mind it’s not the size itself of the enclosure since I’ve seen plenty of 500g adult males go fine in a 20 gallon tub or rack, but 20 gallon longs are so skinny is the problem, a wide bodied animal in a narrow area doesn’t fare well generally if it’s trying to explore or find somewhere to get comfortable. The second thing I’ll say is that I house my ( small, stunted, or juvenile) ball pythons in roughly 12 gallon racks because it’s plenty of space to move around for them… at the moment. This is where the confusing part starts, after the racks or tubs or whatever I feel necessary to start a BP off in, it’s completely depends on the size and behavior of the snake afterwards, I’ve personally NEVER had issues besides the very start of ball python keeping having a nervous animal, but this is because I follow the “rules of cluttering” that I keep in mind while putting together an enclosure, I also put them against a wall so at least 2 walls are covered for them, preferably 3.
Now you may ask “what the hell does rules of cluttering even mean, it sounds a bit unnecessary” and I’ll be honest it is but it helps me keep a little checklist in my mind all the time, and I flex it depending on the snake. The rules of cluttering are essentially 1. Have a basking spot 2. Have a good heat gradient 3. Provide some form of light for a proper circadian rhythm and proper eye management 4. Have at least 1 actual hide and 2 safe spots/hiding spots or 2 actual hides 5. ALWAYS hard scape (wood and rocks) diagonally first to provide more security and dimension 6. Plant, real or fake, by each hide and in each available corner 7. At least one rock to help with shedding 8. Water dish in the center of the cage so the water doesn’t get evaporated too quickly 9. Use enough substrate where it’s about the same thickness of the ball python’s body MINIMUM for proper humidity 10. Always while in progress, at safe steps, let the ball python explore the cage a bit to get more familiar with it over time and to ensure that it’s a setup your ball python feels comfortable in
As for actual cage sizes, I aim to go for the length of the snake with a more width to it than half the snake’s body. But sometimes I have snakes who just don’t want that! They’ll generally let me know by acting stressed or just having discomfort, and I’ll whip up a new cage for them. I’m gifted to have the resources available to do that but generally this is either clutter changes or a cage swap with somebody. Best examples I have right now for cage sizes is I have a full grown nearly four foot female in a 40 gallon because she’s comfy, but I have a 500g hardly passing 3 foot male who gets his own 6 foot long enclosure. As for stress issues regarding bigger open enclosures, either it tells me I screwed up on the enclosures insides or I screwed up on the enclosure in the first place. Overall my goal is to at least work them up to a cage that I feel is safe and healthy for them and I’ll refuse to let them stay in too small of and enclosure for health reasons, or too large of one for escape safety reasons. In a bit here I’ll attach some images of my enclosures for some of my animals as examples, currently it is renovations and cleaning day as I announced in the chat meaning today is a good day for chipping in with actual images in tow too.
Overall it’s all very variable but it boils down in my head to what size seems safest and healthiest, which includes me asking the questions “does my snake feel safe?” “Do they have enough space to exercise and stretch out fully?” “Can I provide the proper resources in that size or shape space?” And generally I should answer yes to these three questions no matter what. Could I put one of my babies into a 20 gallon long, close the lid after some lid modifications, and call it good and most likely if set up properly it would be good? Yes. Would this apply to my 1300g+ snakes? Absolutely not. It’s all up to the owner, but it’s also up to the owner to realize that there’s no true answer as to what size is best or correct besides the one that is individual specific for your snake and ensures they’re a happy, healthy, stimulated animal. I also stress stimulation since a lot of racks don’t do that and they’ve done studies that underdressed dark racks can cause developmental issues, so so much as some wood and a plant can do wonders, for my ball pythons I just decorate their cages to hell, but my garters even get toys sometimes which they’ll perch themselves on and bump around, even if it’s something like your snake smelling a new or different smell, or feeling a new or different texture, it does wonders! In a bit once I’m done with some enclosures I’ll attach pics and examples of how I do my enclosures 
In the end I agree with TikTok about how a 20 long is generally not suitable for an adult since it usually does not provide the proper space for tools to a ball python’s success (as in developing properly and living a good accommodated life) but I disagree with the fact you were bombarded, it’s never ok to bombarde somebody when it covers something like animal care for the better good of the owner and for the better good of the animals.
