Okay, but normally people list LXWXH in their cage dimensions.

A rock is fine in the basking area. A good idea that I employ with my acanthurus is 3 layers of flat rocks with spaces of about 2 inches inbetween under the heat light. It gets to 150 on top, with drops of about 10 degrees per layer as you go down. It provides extra hides at different temperatures and looks kind of neat. Some people use plywood, but I like the appearance of the rocks better.

Chris