I had to take the machine to the shop because it was out of timing, which is probably what got it put out in a garage for all those years. But I got a wooden prototype of the bracket done and it works
It does need to be a little farther away from the handwheel, but when I make the metal one it'll be more stable. The wood actually cracked on me but when I held the thing still it stitched successfully. It's one of the new cranks from china with the rattly handle so I have to do something about that too.
It looks ugly because I was blasting the paint off to repaint it matte black and ran out of time to get it all.