Yes, I wanted to make my own. I like refabricating my bike parts using home-sourced items. It gives that organic touch.
The key question is the thickness. I think I can figure out the other aspects. I tried an aluminium washer in there that fit well but then the wheel had a bit of play at the rim when fitted on the bike. So I took out the washer and now it does not wobble but there is nothing to separate the oiled pawls in the freehub from the greased wheel bearings which seems imperfect.