I have a few questions Dave. How fast do the roaches grow and how old should your cham be before you start feeding him/her roaches?
Howdy,
Good question about Dubia growth rate

. So much can depend on how much you feed them and what temp you keep them at. If you need to slow them down, shut-off the heat and reduce the food to maybe once a week or less. Otherwise, I think I read that they will produce a batch of nymphs every 60 days or was it 30 days

. As hallenhe said, the small ones are a nice size for the typical 3-4 month-old Veiled or Panther or anything in that size bracket. My adult Leopard Geckos almost never pass-up a Dubia

.
I had Lobster roaches for a few years but I wasn't a big fan of them since they smell like dirty socks, climb glass, the babies are super small, and they seem to be able to survive cold to the point that I think they might do well if they got out in my house

.
Lobsters:
Although this is a photo of a batch of Hisser nymphs (I don't keep them anymore either), you'll get the idea of what 10 minute-old Dubia nymphs look like:
(See page 90 of "The Chameleon Handbook" 2009. Yep, that's my hand

).
I think it's a Hisser... Neat looking anyway

.