Jeff,
I find that interesting that you see a Button base in the Mayo Spur picture, I see a Dogbone, but you are correct on the crank-arms to id these differences in the manufacturer. I'm still looking for the two-way top-plate with dogbone-base.
Jeff,
I have wondered if the C&S Handle was a replacement casting or a C&S cast complete stand under licence, if they did it that way? I have read where the RR Companies paid royalties for such things as Priest Flangers so I see no difference to producing switchstands.
UpSideDownC
in New Zealand