As long as the epoxy is still dentable with your fingernail (green stage - epoxy, not your fingernail) you apply the fill coats without sanding. You definitely should try to do it that way. If you are filling using a foam roller, you can stop after 3-4 fill coats after wet-out. You'll probably end up putting another coat on much later after you've sanded everything smooth.

> I just put glass on the hull of my G-Coastal. What a nerve racking first
> experience. My question is this...How many fill coats of epoxy do I use?
> If it is more than one, do I sand between or will it level out as more
> layers go on? It's my first time with epoxy and fiberglass so any help at
> all would be greatfully appreciated.