Iv'e used K&B Polyester for 35 years, and I for reasons you Mention, it is great for surfacing. and I have sprayed
it with a $13.00 buffalo touch up gun with Great success. It is fast and can be flawless. But as far as layup's go
I like Epoxy glass fuses. It bonds to better during construction. It is amazing just how much they are alike, after they completely cure.
What are you guys using to install formers in your jets? From what I can tell, Hysol is the product of choice.