You said..."Do you recommend there still be a sandy base in case the chameleon is gravid and needs to dig? "...what I do is put an opaque container about 10" long by 6" wide by 10" deep 2/3rds to 3/4's full of washed sandbox sand. This gives the chameleon a place to dig if she needs to lay eggs. She might have to be moved to a larger container when/if the time comes. By having a container in the cage, you don't have to worry as much about missing the sometimes subtle signs that she is ready to lay eggs.