I am going to add to what Larry said above. It has been my experience that when you need a centering gauge, then something is out of specification. Ford never used a shoe centering gage when the shoes were installed on the assembly line. On the original factory print, Ford's engineers specified a two-thousandth of an inch variation to be the maximum that the Brake Shoe Centering Bracket be located. That is about the same specification as the thickness of a human hair. Think about that for a bit.
It is my opinion that most hobbyists do not have the ability to be able to match that critical tolerance. FWIW, -Ford did not allow his Agency mechanics to change out the Centering Bracket during brake work simply because they could not hit the correct location either. Chances are that if they could not do it, most restorers today cannot do it either.
Unless you have the proper fixturing to be able to correctly locate the bracket, you can miss it by 0.020-0.030 when the size of the rivet shank and the hole in the housing plate are all factored in. This causes shoes to be located incorrectly in the parabolic shape of the brake drum. Unless you can make sure the centering plate (track) is properly located, and the head of the pin is the proper size, then you are not going to have braking ability as these were original designed to have.