I am in the process of paint prep now. I have DA sanded the entire body with 80 grit down to bare fiberglass. The body had (6) coats of material on it when I started the DA sanding process - powder blue gelcoat, color, primer, color, primer, color. The next step I applied Eastwood 'Contour Premium Body Filler' where needed to provide a flat surface and to properly align the doors, hood and bonnet surfaces to the surrounding fiberglass body surfaces. I then sanded that with 80 grit using a long board sanding block. Next, I applied 2 wet coats of 2-part black epoxy primer (Eastwood #2785ZP with #50243ZP activator) then sanded that with 320 grit using a long board sanding block. Next, 3 wet coats of Eastwood 'Contour Gray Polyester Primer-Surfacer' then applied black powder guide coat and sanded with 80 grit until I removed most of the guide coat leaving guide coat in the low areas, I cleaned the surface and applied more Primer-Surfacer to the low areas, applied the guide coat and sanded again to remove the guide coat. I repeated this Primer-Surfacer/sanding process until I was able to remove all of the guide coat without sanding down to the black epoxy. My finish sanding on the last coat of Primer-Surfacer was 80 grit, then 120 grit, then 180 grit, then 220 grit, then 320 grit all with a long board sanding block to keep the surfaces perfectly flat. I have yet to start applying the color coats and clear coats. One thing I did find during the DA sanding - when I sanded over areas with spider cracks in the paint, the cracks were only in the color, and not the primer or fiberglass. I think since the body is so thin and it flexes enough to crack the color coat in high stress areas - around door handles, etc. I reinforced these areas with (3) layers of matt fiberglass on the inside to give more strength to these areas.
Tom
74 TCS - 4605R