Substrate COULD cause impaction. It will also hold moisture which COULD be host to lots of bacteria because it doesn't have any way to drain itself like in nature.... so.... why take the chance?
For veiled, look at this site: http://raisingkittytheveiledchameleon.blogspot.com/2007/12/supplements.html
For panther, look at this site: http://www.prismchameleons.com/Care.html
I'm not sure if he's that particular chameleon... maybe Harry knows?!? Hades' cage was set-up beside the cage kit that was for sale if that helps. His parents are Hollywood and Winifred from ChromaChameleon (Barrie).
Our boy (panther) now has a name... Hades. His father's name is Hollywood and his mother is Mercedes so it's kind of a blend of the two plus a cool name to begin with.
Oops... mother is Winifred, not Mercedes... oh well... his name is still Hades!