There is almost nothing to the model. There are brass inserts that go in a pocket and then an outside cut to what ever size you want.
The kit for the insides comes with instructions for the brass insert part but the outside dimensions and the width are not listed. They do ask for 3/4" thick wood but that is too thick I think. I think mine might have been a bit thick but it was my first one so it may take a few tries to get in the zone.
The diameter is a personal preference, and since I don’t have one I guessed that somewhere in the 55mm to 57mm range would be good. Since I planned on turning mine after this wasn’t critical in my design or the SO cuts and I didn’t go back with a clean up cut so you could see the three steps I used to cut it.
I have one more kit to make one for myself, I would have normally done that first but the Birthday thing had precedence. I have more of the same wood so this next one will no doubt look pretty much the same. I’d like to have a go at some engraving but have yet to practice even. We will see how brave I get.
What makes this an interesting project is that the center brass is a press fit so you can do an off set then work your way to the fit you want. I’ve done that on several similar projects is a great feature to have. If I get brave enough I might go full size next time to see how close that would be, if it turned out too loose then glue is still an option. And if it too tight I can fix that with the off set. Just getting use to trusting the tools.