I am fortunate to have a rebuilder shop close by that I know the owner. He is second generation rebuilder that rebuilds mine the way I want it using the parts I want. He is much younger then me so hopefully he will be around until I am done fussing with starters. I can think of a million things I would rather do and can do with my time for the nominal rebuild charge .This has worked for me for decades . Maybe find a rebuilder in your area that is open to rebuilding your starter core and you doing the final detailing once it is done. Just a thought.