I started with 220 grit wet-or-dry paper, but it was slow going. I was able to find 150 and that helped a lot. Went over them after that with a quick pass with 220 and 400 grit before cleaning the wheels and letting them dry. Plus a little touch up on the road rash with a dremel. Then prime, paint and clear.
I initally thought I was going to bite the bullet and break the wheels apart, so this project got delayed while I pondered. I was dissuaded by the sheer number of titanium bolts to remove (80 on the set) and that the cleaning would be that much more involved -- no longer an afternoon with some sandpaper, but sending them out for media blasting. I decided that it would quickly grow from an afternoon of working on the car with friends to a week long process of removing them, getting the tires taken off, media balsted, refinished, etc. I decided that I wouldn't let the perfect be the enemy of the good and do it myself. So for $24 in spray cans I got a big improvement in appearance. I had one estimate of ~240 to powder coat the wheels (delivered to him with tires), but without breaking them apart. That was going to be an unknown extra.
Here is the write up that I referenced earlier, via Renntech.
https://www.renntech.org/forums/topic/24183-split-rim-wheel-refurbish-sport-design-style/
And then follow the link the a PDF.
Comprehensive. And he broke two of the bolts when removing the centers. He was lucky in that when they broke there was a stub long enough to grab on to and remove.