I would go with the CB-70 size

Animal Plastics makes great products.

http://www.animalplastics.com/

Either way Reptile Basics or AP you will get a great rack and great service.

Honestly the professionally made PVC racks are much better than home made racks. They hold in heat very well since they are enclosed and are manufactured by computer controlled machines that make the parts (and future replacement parts if needed) exactly the same with an incredible amount of precision.