What size should I do?

[Regius_049]

You will find most people use the CB-70 (made by IRIS) or equivalent tub size for adult ball pythons. These tubs measure approximately 33.5 x 17.7 x 6.0 (L x W x H). It is impossible for me to argue you can't keep ball pythons in these tubs, because there is a plethora of evidence to the contrary. However, I do think these tubs are too small for a permanent enclosure. They have too little floor space for larger specimens (you can't really fit an x-large hide in there) and they are only 6" tall, which is very little head room. As a quarantine tub, CB-70 tubs work well. Regardless, many commercial rack systems exist for CB-70 tubs.

I would encourage you to try for a cage stack of PVC or other plastic enclosures. You will find most people have great success with, and encourage the use of 48" x 24" x 12-15" enclosures. Assuming you are gunning for a 36" or 48" size, they really don't take up much (if any) additional space. For example, a reptile basics CB-70 rack is 34.5" Deep x 19.25" Wide x 30.75" Tall (61.50" if you stack two) and any rack you might build will have to be similarly sized. A stack of (5) 36" x 24" x 12" cages is 36" x 24" x 60" with no stand. You for sure lose "volume" of snakes per unit area, but you have much more appropriate enclosures.

If you are dead set on a rack setup, animal plastics has VE-175 tub racks they use for larger constrictors. These tubs are 52" x 20" x 12", which might be a bit overkill, but there are not a great deal of tub sizes between these and the CB-70 unfortunately. If I was going to do a rack setup, I would build one designed for these tubs or just buy one from animal plastics.