Depends on the resin used. If you use a good laminating polyester resin, you can probably lay out 10 layers of glass - no problem. Cheap Bondo brand resin, one or two layers tops (it will twist / warp with more so you have to gradually do layers at a time). With decent epoxy, you can do 10 layers no problem.

You could lay in towels or some other foam padding to give the additional room needed under the carpet for wider cradles. All it takes is a little tape to hold it in place.