RE: what do you guys think of this Spine Tester
Yep very cool.
The one we have at our shop, made by the folks who make the ratchet press has a special "hanger" for the weight also so that there is no interference.
Unfortunately, like this home-made model, the one by the Ratchet-lock people is set up to test spine the way wood shafting is..i.e. measured over a 26 inch span. Modern alum and carbons are tested over 28 inches. My shop modified theirs so it would measure to AMO/ATA specs (28")