I know what center shot is, I am just curious as to what others consider center shot and how they find it.

I am a big proponent of walk back tuning. I will first of all set 2nd and 3rd axis on a medicine stone bow vise. Once this is done, I will first shoot a 3 arrow group @ 20 yards and then walk back to 40 yards. I will hang a plumb bob from center of the 20 yard group and then shoot with my 20 yard pin or scope setting from 40. If the arrow drops vertically and I am using a pin sight, I then go to check paper tears at 5, 10, 15, and 20 yards. If all appears well there I let it be and sight it in. If I am using a scope (like on my FITA bow) I will actually walk back tune it to 70 meters. The most I cancomfortably hold a predictable group is out to 70 meters so that is why I will go back there instead of 90 meters w/ my fita rig. The place where I do a lot of my tuning has 60 yards indoors so I can do this kind of walkback tuning so that the arrow doesn't have wind to affect flight for the majority of it.

As far as papertuning for spine..........................

I have read a lot about this, but nearly every arrow I shoot is overspined according to OnTarget2 and any chart you might see because I shoot a lot of linecutter style shafts for spots, and 3D. Specifically I shoot Pro 22's and 30X Pro's. I never see symptoms of overspine on these arrows in terms of nock right tears once my walkback tune has been completed. As a matter of fact out of the 6 different types of arrows I have made up right now for different purposes only one set is spined correctly, and that is my skinny K&K Angel 405's that I use for out to 90 meters for FITA. Do you guys actually see these types of tears for too stiff of a spine? If so, why do I not see this?

I know a lot of guys that say that spine is so critical of accuracy, however I am shooting 445-448 with34-38X's on a 3 spot vegas face right now. When I miss, I know it isn't because of the spine, it is because of a poorly executed shot.