it took me about 3 hours to do one wheel, although I started with the best condition one.
Every one does it differently, but I use P38 easy sand on any bits that need sorting, rather than spending ages sanding I just used a dremmel with a grinding bit on and any bits where the paint had lifted just blasted it off with the dremmel and then fill. Sanded the rest down starting with 120, then 400 then 600.
I then used a high build primer which is good at covering any scratch marks from sanding. Did 3 coats of primer, then really really lightly rubbed it down with 1200. You have to be light as the primer comes off really easily, once super smooth clean with white spirit and spray very lightly with top coat, hardly even covering it. Then apply 3/4 more heavy coats untill you have a nice even finish etc...
this is what I am kind of aiming for
