Thanks to "Ross F1", who sent me some nice stainless steel shim stock, I was able to get my clutch fingers all within .010" of each other. One required .007" while a second needed .002". I think the .010" is about as good as can be done because of the geometry of the clutch fingers. The hardest part of the whole thing was drilling the holes in the thinner shim stock. I ended up punching them with a one of the hollow punches I have for making gaskets. (I think it needs to be sharpened now.)
Thanks Ross, and also "Fordors" who set me on the right track.