Len, I was hoping to learn an easy way to measure the spine, or at least compare it between arrows in a batch. I' m guessing the arrow is suspended between two points, with a weight tied somewhere, and a deflection distance measured. I' d like a little detail on this. How is the defection measured accurately? What distance apart should the rests be, where the arrow is suspended from? How heavy a weight, or does it matter? It' s something I' ve never measured, and I' m very curious how my goldtip XT would do. They appear to be fairly consistant in weight and straightness, now I' m wondering about spine consistancy.