Hi: A friend of mine who is familiar with rotary engines, and also in the racing,told me that he lapp his end plates with “valve grinding paste”
I thoughts that i gonna give it a go.
So i used some old endplates for practice and experimenting with fine grit valve grinding compound ( waterbased).
It actually came out,very good with  little “reaching and markes” ,of the  old side and corner seals.
This was only about 5 to 8 minutes of rotating with the hand,with only the weight of the plate, and the fine grinding compound.I know that the 2 faces is not “match mates” but the surface is 200 % better off than “ just as it is.

I believe there is still sufficient chrome coating left as you can still see the old corner seals ”path” against the light.