I want to seal the raw surface on the rear of various body panels.I was thinking of some sort of rubberised stonechip.Brushable would be good.Welcome your thoughts and what you suggest product wise.

I have used Tetroseal underbody sealant on two different Strikers now. It is thick enough to seal and protect the underside of wings from stones chips etc without adding to much weight. Also used it on the rear tub, nosecone and bonnet to protect them a little plus gives a better finish to the gel coat by having an even dark layer on the inside IMHO.

On the first Striker it still looked new when I sold it after 18 years

Current Striker is now nearly 7 years old and again still looks like new. Only done about 1300 miles but most on track at up to 120mph with the odd stone (cough....or cone!) flying up under the wheel arches and no issues with cracked gel coat or carbon (front wings are carbon)

The rubber stonechip stuff will add a fair bit of weight to a fibreglass panel. I left my rear tub, bonnet, side panels, scuttle, nose cone & front cycle arches bare, but the back of the fibreglass seats, that are on show, I sprayed with some matt black paint from rattlecan just to improve the look. The inside of the rear arches, I glued some 10mm foam camping mat to stop stones impacting and causing damage, very light weight.

On my JBA falcon I simply used underseal on the inner wings and it did the job and lasted many years. Never got any stone grazes or damp soaking in despite being used all through the winters.