And spine testers don' t really " test" the spine- they just find it and see if it' s unusually severe...
Sorry, I have no idea what you are talking about. Maybe you could explain this a little.
Spine is basically a measure of the stiffness of an arrow shaft. It measures the deflection a shaft when a two pound weight is suspended from the middle of the shaft when the shaft is supported at two points 26 inches apart.