I think it's important to keep in mind that scantling recommendations are for people who are not going to do destructive testing of sample panels. Scantlings provide safe guidelines for builders who use average materials and have average workmanship.

It's similar to the rules-of-thumb used in home construction, such as a 2-by floor joist can safely span a width in feet equal to it's depth in inches. Certainly if you know that you have stronger than average 2x10s you could safely increase the span, but most carpenters don't test load their joist material to the point of failure to see if they could use lighter joists. They're more interested in building the house.

Lots of strip boat builders are going to do just fine with .25in strips and 6oz. glass inside and out. Some people are going to build lighter boats and some will build heavier boats. And the vast majority of all these boats will perform just fine.