They used to be in 40-breeders, which are 36"x18", and did just fine. The adults didn't show a tendency to climb like the babies do, except for the one time my female escaped...
Currently they are in a Monster 96"x30" that is divided so each gets 48"x30", and while it's way oversized for them it's the best enclosure I've got for maintaining the high humidity they need.