Schleicher has a "Maintenance Instructions" for paint cracks he
http://www.alexander-schleicher.de/t...ackrisse_E.pdf

another interesting tidbit:

" we suggest to spray the sanded surfaces first with polyester
fillers, to sand then again, and to respray them finally with a white
paint system on a polyurethane basis.."

i.e. ditch the gel-coat.

John Cochrane