ORIGINAL: HEAD0001
It depends completely on your grip? Are you shooting a locked wrist? or are you shooting a broken wrist?If you are shooting a locked straight wrist, then cant away. If you are shooting a broken wrist grip, then you can not cant.
IMO, spine has nothing to do with your grip. Your release, yes. But not whether you are canting or not.
The book that Fred Asbell puts out on instinctive shooting goes over this question thoroughly. Tom.
I don't even thing Fred says you can't cant with a broken wrist. Just about every longbow shooter has a broken wrist, and I rarely see one that doesn't cant.