I would tack the strips to the forms with the electric glue gun. The glass will hold the shape not the fill coat. The inside will be OK since the strips were against the forms. I highly doubt thin strips would cause your problem. If anything, thin strips would have less a tendency to pull away. For some crazy reason, perhaps the thicker sections are doing more pulling than the thin areas causing some kind of tension?? I have to disagree with the perfectionist. I would get it to work and not start over. You can do your perfect boat next time when you have the experience. This is a learning event and part of that is fixing things reasonably. You WILL end up with a really nice boat that paddles fine.

Get it fair, glass it, fill the weave and let it set for a week so the epoxy / glass hardens. Be careful on those areas you know are thin when doing the inside.

One question; how did you sand through strips? What grit were you using and was it that unfair? I always tell first time builders to use 1/4" strips for that exact reason.