The curve relates to the 'bounce' of the bow and how it is used in certain situations. Classical tighter, old time very slack I covered all this above.

This is all great but I can't help feeling its a bit of an emperors new clothes trail. I'll post a story by a (now dead) top luthier in my next post (so you cna ignore it if you wish) whcih may help to illustrate - BTW I'm not saying it is a waste of time - we cna all add ot our knowledge, I am just dubious as to the outcome.

Andy