Yup those tubs are made just for up to breeder size females. The only snakes that ever look cramped are the 4,000+ gram girls.
This is a very good point. I have a 4000 gram female that are in a rack that uses 41qt tubs that are comparable to the size of these tubs, only these tubs are about and inch shorter. When I feed her and she coils, it's impossible to close the bin.