Here's a very handy tool to have around the hangar, and you can find it in the aircraft tools section of your nearby Harbor Freight tool place ;o) This angle finder has a magnet on one side, which is great when working with ferrous metals. The other side has a flat and a longitudinal notch so you can hold it square against a round tube. In this photo I've got the magnetic side stuck to the Cleveland brake disc. The camber was adjusted using tapered shims, and is now almost perfectly equal on both sides, 1 degree positive.

Here are the tapered shims that are used to set the camber angle. These are available through Aircraft Spruce and are made by Grove in thicknesses of 1/2, 1, and 2 degrees and can be stacked to give combinations of those angles. As you can see, this side really needed some correction... two shims of 2 degrees each.