If you go with the 4'x30" footprint cages, that should be plenty of room... I would add the optional basking shelf. Mine are in 4'x2'x either 18" or 15" with basking shelves but mine are all males and will likely not outgrow them... If I had it to do over again, I'd go with the 30" deep cages instead just in case. I heat mine using flexwatt from AP and I have a herpstat 4 so that each cage has its' own channel. I think some people do heat a stack of cages using one channel, if all heating elements are the same, but IMO it is easier to regulate if each has its' own channel.

I would also opt for the door locks (I have the sliding glass doors on mine with locks) and AP now offers recessed LED lighting (not on their site, you have to call them about it) and that is a great option as well. Keep in mind you will have a ~4 month wait for your cages from the time you place your order. It is worth it, but can be hard to wait.