That looks like a good, workable fix. I tip my hat to you. But why doesn't HD just put the cammed axle system ... a la FLH series ... on all its bikes? What could be simpler?
Even better and even cheaper. After I had gotten alignment dead on with the magnet method to center of nuts, I then checked the distance on each side from alignment hole to outer circumference of the axle nuts. They are exactly the same dia on each side so you can just use anything to measure them. I now use a brass welding rod with a plastic tie cut to a point I can stick in the alignment hole.
Seems like this is the method H.D. should have illustrated. It's a straight measurement.