I ended up using Don’s mounting bracket with my wedge design. I got everything working with a #6 machine screw, but I couldn’t get the design to work with the 1" ones from the rest of the MPCNC build. I had to go to a 1.5" screw.
I posted my files at: https://www.thingiverse.com/thing:4637470.
I’ll post some pictures of the parts once daylight hits and I can get out to the shop (no lights yet!) where I’m assembling the machine.
I also designed some different mounts to use with the motors, since I’ve got a burley and not a primo. I can post those if anybody is interested.