Panther Geckos grow up to 6.5 inches (the "jumbo" form) but, on average they are around 5.25-5.75 from snout to the tip of their tail. Their care is quite a bit different from leopards. They like higher humidity, they dehydrate fairly easily in a heated enclosure. With that in mind you may not want to divide your aquarium. Picta are about as easy to care for, but I would rarely handle them (knowing many people let their leopards "watch" t.v. with them). I love these geckos to death for some reason, many people think they are boring captives, but if you give them stimuli (dead leaves, "fallen" branches, and other leaf litter), they are as fascinating as Rhacodactylus in my eyes (plenty will disagree). They are very hardy when cared for correctly and also very easy to breed (by no means making them worthless animals; no life form is worthless). I would just get a 10 gal. glass aquarium. Two adult females will live comforatably in something this size. You can find them in as many distinct phases as a leopard gecko also (I am working with amels, and many other forms). My number one favorite...
Ashton,
Gekko Terra