At some point I had a similar case with set screws. In my case I needed set screws that were correct in mass to 0.1 grams, and fortunately I needed a bunch.
Our solution was to batch process a bunch in large steps, 100% measure, and then make just a few special to fill in whatever gaps our process didn’t naturally fill.
If I were you I’d get a bunch made at a shop with an automatic grinder or a Blanchard from say (making up numbers) 0.002” to 0.004”, then sort into one tenth steps. Use off the shelf shims to get you close, then use one of your customs to fill whatever gap remains.