I personally use the 28qt 1856 model (23 x 16.5 x 5 5/8) I used to always worry whether this would be big enough for long term housing, and breeding... then I went to visit Corey Woods and my worries were erased. Corey doesnt use anything bigger than Rubbermaid 28qt 2221's ( 22.9 x 16.8x 5.9in) for adults, whether it be for breeding, or housing his 11lb female (she's huge LOL). When I questioned him on his use of a smaller tub, this was his exact response... "In my experience anything bigger and it messes them up" ....for proof of his success with this method, go check his breeding records, Corey hatched out over 500 babies this year.....I also know of breeders that use bigger tubs for normal housing, then switch to a smaller tub for breeding, in an attempt to increase success (with the thought that a smaller space makes them more secure, and secure snakes breed better).....now there are also many breeders who use bigger tubs for both housing and breeding, and they seem to have alot of success as well I guess it all boils down to what you feel comfortable with, and have success with