I'd prefer to keep them all together(but divided) in the same cage. We made it ourselves and I must say it is pretty nice haha. I'll save the 20 gallon for the next snake once I get this all figured out and fixed!
We have heat ropes throughout the bottom of the cage. Both are on a lamp dimmer thing and are monitered by two thermometers. One on each side of the cage. We don't have a device to measure the humidity in the cage but we do have a humidity box in the cage for them to hang out in if they want and they shed in one piece. We also have the heat lamp on a timer.
Also Nick seemed concerned that feeding them in thier enclosures would make them more likely to bite you when you handle them. He also said that they could swallow thier substrate and that would be bad for them.