If you mill them and turn them over, how would that bring you back to the original size? Mine had opened up from 6 to 7 because of the dent. I do have to wonder if they’ll last as long flipped over. The pad on the inside of the follower is larger than the dent but not by a whole lot, so it might start denting from the top.
I mainly found it interesting that only the exhaust side had the issue. On the other side several had closed by a thou. I’m now thinking that on the exhaust side the shim takes the beating from the compression stroke and on the intake side the valve seat takes more of a beating because the valve is closed during compression?
I spent a couple hours last night hand sanding 3 intake shims on a flat stone with emery. What a pain in the butt, and now my hands are all cramped. I’m thinking now of getting some kind of arbor turned with a 17mm recess in the end, and a smaller hole inside that one to place a rare earth magnet. That way it could just be chucked up in a drill press and perfectly milled in a few minutes.