I’ll be drilling some new holes in the fiberglass, and I’m looking for what type of caulking people typically use for sealing between the fiberglass and new plastic pieces that are installed.
I know I’ve read this on here before, but bizarrely can’t find it in the posts that come up as search hits, so thanks for the patience.
Dicor self leveling on the roof, Proflex on the sides.
On rereading your post you say BETWEEN the fiberglass and plastic, Dicor is not used as such. It'd be Proflex as Jim mentioned. Butyl caulking tape could be used too.