I'm from St Thomas - was in Bill's today and picked up two of the small guys (a male and a female) for myself - you can start to tell the males from females in there now, look for smooth skin under the belly region which indicates a male.
Were you planning on getting the large ones or the juveniles?
For the juveniles, people will disagree, but a nanocube will be OK for a while (atleast 6 months)
Ideally, if you are planning on a long term home right from the start then I would say a 29 tall is the way to go for 4 maximum.
Mark
PM me or contact me on Bill's board (mark0933) for any other Q's