I had a machine shop make me an aluminum board for a Sinar/Technika adapter to use on my Kodak Master 8x10.
Since I was in for two hours of his time, and a respectable amount of of aluminum, I asked him to make three more boards.

All three have a Copal 3 hole (60mm) cut in them.
All three will fit directly to a Kodak Master 8x10.

I also had the surfaces roughed up for painting and applied two coats of flat black primer to the inside of each board.
The exterior is original aluminum, which can be roughened easily to apply paint, if desired; I like them silvery, so I left the front that way.
The material you see that fits in the KMV's female grooves is black velcro (the soft half).
I took a lighter to these to prevent any residue flaking into the camera.

They are crude, and they won't win a beauty contest, but they work.
I have no Copal 3 shutters, but all three passed a long flashlight test.
They fit in the groove very well, and don't shake about; the velcro helps fasten them.

If they don't work, I'll refund money without hassle, but they appear to do the job just fine.

The price I am asking is what I paid for the machinist's time and material for the three boards; the extra work is on me.

$50 each plus shipping; I'll cover Paypal fees.

Thanks