spine stiffnes isn't something really visible...you'd have to get a more experienced guy to explain it. or check the article archives. i'm sure it's been explained on here before.

I wonder if the string hitting you is a brace height problem.
i found this little guide to determine correct BH I took it from an article. Here's the link you might want to scim through it. Thereis some good info in there.http://domino.htcomp.net/bhn/Columnists.nsf/0/6d6e03a01d94a96b86256e8d005e6066?OpenDocument

Straight limb self bow 6.0" - 6.5"
Straight limb or reflex laminated longbow 6.25" - 6.75"
Reflex - deflex long bow 6.5" - 7.0"
Recurve self bow 6.5" - 7.0"
Hybrid Long Bow 7.25" - 7.75"
50's Style Recurve 6.75" - 7.25"
Modern Hunting Recurve 7.5" - 8.0"
Modern Target Recurve 64" or longer 8.0" - 8.5"