Any reptile can only grow as big as their environment will allow within the limits for their breed. For instance, if you kept a green iguana in a 50 gallon tank, it wouldn't grow any larger than what is comfortable for their tank. The upright cages are to allow them to get as high up as they want which also depends on what kind of reptile they are. If you aren't keeping your reptile in it's tank all the time, then it's probably not a concern. For lighting, you might try the full spectrum lights and I've found that a couple of well placed heat rocks do lots more for them than a heat lamp. Since reptiles have to get their body heat up to digest their food, putting heat right on the body helps this happen faster.
I don't know about all reptiles, but I do know that I bought a male iguana to go in with the male iguana that we already had. After about a year, my hubby kept saying that the young one looked pregnant. As I had personally checked to make sure it was male when I bought it, I just laughed. A couple of weeks later, I came home from work to find eggs - lots of eggs. My SIL is friends with a herpatologist and he said that if you put two iguanas of the same sex together, eventually one will change sexes so that they can mate. I've had my iguanas for 15 years and they've laid eggs twice. The last time, the male ate all the eggs.