I agree with the "how much hammering"
In my Shrike I glassed the hull both inside and outside. The deck inside the cockpit too.... I think... I planned to, but I have to check that :-)
Mainly because I dont spend much time on flat water and I do land on beaches.
I also taped the seems inside, but would probably not do that today.
I used a lighter fiberglass inside the hull than outside. It was only 80 grams/m2. And I also tried to reduce the amount of resin I used not to add to much weight.