For the most part, fin boxes are stabilized by the glass on the flange so you want to make sure that local area is strong. Most glasses will add an oval patch about 8 by 4 over the fin box so that there are two layers of glass. These go under the full length glass. Alternatively you can lay a larger patch over the whole tail end. This would add a little more weight but makes blending/sanding the reinforced area a little easier. Good luck.
for sure if you tumb push 6oz on 1.9lb you can dent easily. but it’s a standard for surfboard industry. The 4oz on pu foam reference build is even more easier to dent so i don’t speak about the 4oz on 1.5lb (and sometimes less) ultra tech light build that’s the “new future”. I don’t know your background but since the 90’s "ultralight surfboards (the 2x4 top 1x4 bottom on light density pu with paper thin stringer), standard strength of surfboards became very low. People complain about durability but seller explain them well that’s it better for their surfing (as extrem rocker thin babouche outline at that time). So if you want real durability go with more glass, for sure your board will be heavier. On other hand you can save some weight with lighter bottom without so much durability lost except dents, if you don’t let your board in impact zone too much. if you want to move to an other durability standard you have to look at “sandwich” or “compsand” techs. a far difficult build to do well, can achieve an amazing strength/weight ratio but with a “hard feel”
Depend where and how it’s surfed. depend strength standard too. It was my standard build, guys i make boards found them lighter and stronger than standard pu/pe, they broke as others, because of our impacted close out beach break here, but ding and dent less, and better they didn’t feel stiff like what was said about epoxy at that time. may be because they didn’t want to feel them stiff LOL. after trying many build tech i move to a slightly more exotic build my boards are now heavier, stiffer, and harder, far less breaks or dings and better they don’t chatter like what said about epoxy boards know, may be because riders don’t want to feel them chattering LOL. a question of education, my main job is teacher. the fact is most of those guys don’t want pu/pe or eps/epoxy shop boards, not because they don’t work, most are better than mine, but because durability, they don’t take any more cares with mine, again an education question.
