I find another issue here. How big the fairing or rounding can be on the edge of the headrest part on the seat back?
Also, I find myself asking again where the headrest support begins here and where is the top of the headrest where the 2 radii arc should touch the top?
I guess at the end of the flat part? Is that easy to find that part at the measuring? Does that issue concern many hulls not covering the minimum radius?