OK,OK, first off, we do use 600 on clear coats prior to second coating and NO sand scratches. "X", we're talking Gel-Coat here, not base coat paint. Again, on a colored gel-coat you wont get sand scratches if done right.
Second point, I think everyone is reading my post wrong. A&C's Gel - Coat finishes are great as is! (Cehck out Roscoe's Gel!) But, if you want it to even look better,.....then opt for the clear coat finish. Even A&C has/had done this to some of their "show-off" cars.
Not a paint Rep., but I've been painting and fiberglassing for over 30 years....and I didn't spend a night at the Holiday Inn!
Ed "DV" Combs .....as David said...always use a wet-sanding pad!