I'm not sure about how many babies are kept together. Just wanted to say that Calypso is about 7-8months old and still in her 30gallon tank. (Though I can't wait for her to be in her larger enclosure.) It has a lot of room for babies, especially with branches or a hammock or two for them to use the upper part too.
I too (well my husband) am getting into breeding. Call around and ask the breeders what they use. From what I have seen most use large plastic bins. They dont keep more then 5-10 so you will avoid toe and tail nips. You also need to make sure that you offer enough greens and feeders.
I plan on using two to three tier bins 5 wide (eventually if I get that big!!) housed in 2x4's so we can mount the lights above the bins. I dont know though how long you can keep them in this type of arrangement. My husband builds beautiful melamine cages so I will probably have him build some that will be empty waiting for babies!
Try looking at Dachiu's sight under breeding facility/baby bins. We hope to have something similar to this someday. They produce wonderfully beautiful dragons!