Mark, with my wheel and the many cracks it had originally I was most concerned with it re-cracking after doing a ton of tedious work. The idea for the methodology I used came from Doug Lepak (his username here is "stwheels") who is one of the vendors here who restores steering wheels. He was forthcoming when I asked some questions about how to do a couple things, probably costing him potential business as I consider myself a real do-it-yourselfer and it was pretty obvious I was fishing for info, but Doug said he 'encased' the wheel in carbon fiber cloth. I suspect that he decreased the physical size of the rim with light grinding and filing, then used a very pliable carbon fiber cloth to build the wheel back up. I decided to remove an even greater amount of original material and then build it back up with plain old fiberglass cloth. I just cut it into long strips and slowly built the rim back up. Of course I had removed the metal trim rings/bands to grind the old plastic away, but when I got the wheel built up to the point that they would slide back into position with a little bit of resistance from the fiberglass base I had been building up, I put them back into place on the outside and inside of the rim. Then I simply continued to build up the wheel alongside the trim with more fiberglass, so they are locked solidly into place with no gaps or space adjacent to them. I continued the build-up process until there was adequate material in place to start cutting and filing the wheel back to as close to original shape as I could. It helps if you have a spare wheel available to compare to, so I think I got it really close. Of course this involved cutting the finger grooves into the backside of the wheel and then shaping them, all very tedious and time consuming. If I was in business to restore steering wheels, I probably would not do it this way again but it is probably a one time deal for me and I wanted to be certain the wheel didn't crack at a later date. I would be concerned that simply filling a crack with epoxy, JB Weld or even the material in some of the specific wheel restoration kits would eventually shift shape and re-crack. That is one reason I liked Doug Lepak's method of encasing the wheel in carbon fiber cloth. I figured that utilizing simple fiberglass cloth for my project would provide a sturdy enough base that I won't have to worry about cracks in the future. Like I said it was a time consuming project, I'd go to the garage and lay on some glass strips, let them dry, sand off any nubs or obvious high spots then lay on more. It's going to be time soon to start cutting in the grain, what I lack in real artistic ability I make up for with patience, so I'm convinced I will end up with something that is up to snuff.
One other thing I noticed is that the stainless trim bands are 'exposed' on original wheels, not buried under several applications of clear coat. I actually have duplicated this look by decreasing the size of the glass build up adjacent to the rings to make them slightly higher in elevation than the wheel rim itself.
Unfortunately, I did not take any pictures of the glass build up process so I don't have that to share, but here is a shot of my wheel with a coat of primer on it and lightly sanded. A bit more sanding and then a coat of wood colored paint and I'll be ready to start on the grain. There's some great info on how to do that right here in this thread. I'll keep up with the rest of the project with pictures.