IMHO, having a machinist make the adapter would probably be safer. I'm assuming you used steel shim stock? If so, keep in mind that it's in an aluminum wheel and the aluminum wheel is a lot softer than the shim stock.
A long time ago, when working as a mechanic for a trucking company that was on a shoestring budget, we used aluminum cut from beer cans to shim the bearings in aluminum front hubs. Never did hear of it failing, and it had 6000 lbs on each front wheel.
My local machinist won't do what you describe, he's concerned about the rider crashing for some other reason and the family sueing him, so he won't do any suspension work at all. At least that's what he said when I asked him to do the same thing for me.