I'll also add that You don't Always have to trade up tubs, I've kept BP's less than a month old in 41 qt CB70's, each with Privacy, Clutter, and 6 hides and I rarely ever get a refusal when it's feeding time. Now I know others have but the simple solution is if the big tub doesn't work you can always trade down.
But yes if your going to have alot of BP's I have to say tubs are the way to go. they are naturally a very private animal.