New Suri! Could use some cage advice

[td30]

My room temps are usually about 77-80. I use flexwatt from RBI on my 421D's. 2 feet per cage, stacked 6 high.

So 11"x24" placed lengthwise? One thermostat per cage or one per stack? If you use one thermostat per stack, is the temp on the top cage hotter than the bottom cage (hot air rising)?