I think the layers of gel underneath the flowcoat will go off. From what I could gather from this site and others gel and flow coat are quite similar, but flowcoat is a bit thinner and has wax in it to seal it off from the air for the final cure.
The wax rubs off flowcoat and the resin is still hard so I think gelcoat will be too once it has cured under the flowcoat.
The reason I went for layers of gelcoat first was that I believed it to be a bit thicker than flowcoat, so I could build up some thickness in each layer to protect against scratches and without the wax I could apply layer upon layer without the sanding. The final coat was with wax so the whole thing would cure.
That was the plan anyway, it is all a bit of an experiment to be honest
I really underestimated the amount of sanding though, I have done plenty of surfboard repairs over the years, and dumbly figured it would be an upscaled version!!
I have given up for day, all my finger tips are raw
I think there is another day of work, working up to 1000 grit and it should be done (fingers crossed!)