One my 33 Gallon (36x12x12) long I have a Exo Terra Desert medium. WIth the sand/slate substrate the surface temps stays roughly 90 (+/- 3 degrees) so I don't have to use a rheostat. During the day I have a overhead 65watt bulb in the center to bring the air temp up. At night I just leave...
Personally I didn't find a way to cut the slate to fit perfectly. I just fit it in and used sifted play sand to fill in the gaps. Some people would say to not have any sand in there but I don't see it being a problem for adults that are cared for correctly with the right conditions. Even...
i keep my adult on a rock/quartz sand setup and never had an issue. The cali-sand I have heard about issues with so I have never used it. I have kept other desert lizards on sand and never had a problem. For juveniles I would stick to something else but for adults as long as the conditions...
Adding grit is what these guys are doing with their mixes and they seem pretty successful. This is why i think all of the debate over sand is pretty played out.
Here is a video showing them putting together their mix...