You actually can do grades of other than 2, 3, and 4 percent. There are illustrations right on the box of the inclines that show you how to do this by combining different sets.
The biggest con is probably the cost. But if you look for the similar discussion over in the main section, you will see that if your grade has to be on a curve, the WS system is by far the quickest and easiest way to go. For straight inclines, the more traditional cokkie-cutter approach, even if you use extruded foam insualtion as your table top, is almost as easy and a lot cheaper.
--Randy
