John,
We have several tanks for our pygmy chams.
The largest tanks are 4 ft long, 18" high. The smallest is the equivalent of a 15 gallon aquarium.
We do not use glass tanks - as you know, glass heats up easily and takes a while to cool off. We have made our tanks from plexiglass (Home Depot) and wood. Hubby is terrific at building almost anything we need...
We have taken to making windows in the ends and front of these tanks (except the largest tank (just windows in the ends). We place fiberglass screen over it, and apply a wooden trim (use silicone to glue it down). This allows for increased ventilation. And that is much better for the chams.
In one of the large tanks, we have 2.6 R. Uluguruensis - and there has been no trouble with over-crowding. In the smaller tanks, we usually keep 1.3 of the pygmy chams, but no more than 1.4.
I use Super Soil (brand name) for the dirt - no perlite or vermiculite. I then apply a thin layer of cypress mulch in some areas, live moss in some areas, and orchid bark (lg chip) in other areas. All of these keep the humidity up, and the chance of soil ingestion down. I also use some of the coconut fiber - fine. But I have seen a few flakes of it ingested, so use it sparingly.
Plant spreading ground cover (available at most nurseries), a small leafed variety; small leafed ivy; small ficus; mini palms; grape ivy; and other low light tropical plants. Be sure to add lots of thin twigs for highways (corkscrew willow works perfect) and some wood burls for accent. Cork bark is neat - but I notice the crickets hide under it, so I limit that in my tanks.
In some areas (around the base of plants) you can place dried leaves (crunched up) for digging and hiding. This is very necessary for the brumating pygmy chams (brookesia spp).
Hope this helps.... there are pictures in our gallery.
Morgana