You're asking for a specific answer to a subjective question. Not the best way to start a conversation, but let the fun begin...
Now, go out and find an Iris MCB-L tub and measure the length and width. That would optimally be optimum for an optimum adult male BP. Now, since you're already at the snake tub store, get an Iris CB-70 tub and measure the length and width of it. That would optimally be optimum for an optimum adult female.
Of course, we all know that some males will optimally grow larger than some females, and that optimally some females may not get large enough to occupy a CB-70 tub, so in the end, your optimal mileage may vary.
EDIT: I think I may have broken some of your rules for responding to this thread. Just call me a First Amendment Outlaw...