Hi! So for starters, yes most pokies should be kept in 10-15 gallons as a full grown (Your preference). However, for pokies such as the P. ornata or P. rufliata, a 15-20 gallon is mandatory; 20 gallons preferably. As for the exo-terras, I'm not so sure...from what I've seen at the pet stores, they seem like a terrestrial enclosure, even with that height. So my opinion, is to just go with the 10-20 gallon aquariums, but remember that it's my own preference and opinion. As for the males, they are a bit smaller than their female counterpart. When I say a bit smaller, I can't really specify because each Pokie has different genes. Another thing, is that males are also usually duller in color and a lot more thinner most of the time. For male housing, just keep the tank a bit smaller then the female's tank. For the female measurements,
P. fasciata: 7 - 8 inches
P. hanumavilasumica: Not sure (Still a very very very rare pokie, and I think it's also critically endangered in the wild...not sure. Check the IUCN and see if they have its conerv. status)
P. smithi: Not sure (Still a pretty rare pokie)
P. tigrinawesseli: 7 inches? Not Sure, but it probably is.
So yeah. I hope this answered most of your questions. Good Luck!