75mm Hypergon on 8x10"!!

I think I can do a better job of getting the inside of the spinner smooth like the vintage original in the picture below.
I might also try some of the super black paint on the market in place of the much talked-about nano particle black that is not available.

Nice work.
By 'smooth' do you mean that you want to get the spinner more flush to the lens, so you're trying to reduce the bulge caused by the bearing ?
If so, I think I agree.

The edges of the screw showing through did not get painted well and reflect a little light. I'm currently re-doing the black paint.

That's pretty darned crazy!

quick followup on my thought about reverse mounting a Sinar shutter. With the lens mounted on the 3d-printed Linhof that came with the lens, and the Linhof lens board mounted on a "Luland" Linhof to Sinar lens board, I tried reverse mounting the assembly into a Sinar shutter. The rear of the lens assembly (not the glass of the lens but the surrounding metal part) sticks too far in by about 1mm or so. For the time being, I'll use the lens cap method to shoot the lens, but I may see if I can modify the model. The extra depth of the stadard is still there, but on my camera the standard has a much larger opening than the shutter, so probably won't interfere.