I've been patching several interior nicks and factory voids that broke through; including great success on the steps. The Catalina parts dept gelcoat was a very close match. Interior is easier since so much less sun aging. I bought unwaxed gelcoat. I used acetate sheets taped over the small repairs or sprayed PVA over when flashed. I'm also using the factory "Regular White" for a large number of small exterior repairs. By experiment, I found that the interior off white worked great added in small amounts to the exterior white to yellow/darken to match. Easier to blend in small batch amounts than solid pigments. For small nicks, the out of the can gelcoat was pretty close after polishing. A lot of trial and error to get a perfect match... I keep the gelcoat in the freezer to extend its' shelf life. /Ed