Its nice that youre doing that and trying to get it back to original.
My thought is this - buy one of those lapp wheels, remove the rubber, make a mold, and pour either polyurethane or epoxy into a mold made for it. Once successful, re-do yours.
Kind of like how they pour these materials to make new bushings. Not sure if/how it would bond... But to me it would be worth the shot. Make a mold out of something you can form or carve. Might be tamped sand, might be something else. Shave down the wheel to the right diameter. Doesnt need to be perfect.