RE: Extra airfoil thickness
We used thinner foilsyears back at 1990's TOC - worked fine -on the bipes some foils were 9%</p>
If weight is low enough the foil can be flat dead flat </p>
no problemexcept structural.</p>
In real world of 1000sq in n up stuff sticking close to 12% allows for a strong shape woith good stall /recovery character.</p>
</p>
</p>