Borrowed THE skin on frame book several years ago with the explicit purpose of finding how to cut n sew stern and bow fabric.
Book wrote: we have no idea how to explain a method.
6 years ago, stumbled over a web site or nag article on an Oregon builder who suspends frame bow or stern down into a fabric pocket. Weight/form in real time then giving cut n sew.
There are several Oregon builders online and several UTUBE video.