SPFs are painted. Their gelcoat is under a primer, sealer and the colorcoat/clearcoat. A gelcoat repair will not help you, you must paint.
For some difficult paint matches, I have taken my cars down to a DuPont paint dealer, not a painter, they have a device that sits on the area you want to match and illuminates it with one or several spectrums of light, then it produces an exact paint mix combination that for me has been perfect. I have used it on solid, metallic, pearl colors. I have had the device produce an original color mix but usually years, oxidation, sun fading will alter the original color.
Not so, they switched to Glasurit a few years back. I can provide a color codes if you can confirm what color white your car is painted (i.e. Wimbledon White or "Hi Tech White).
