Super Simple Arrow Spine Meter

Hi there, after looking for a super simple way to test and meter arrow spines, with no success in finding something simple, I have created my own version based on some videos and ideas I found in Internet.
Arrow Spine is being measured supporting the arrow between two supports 28 inches apart, and then pushing down the middle with a force of 1.96 pounds. The amount of deflection measured in that middle point, in thousands of an inch, indicated the Spine of the arrow. The higher the Spine, the more flexible the arrow will be (for bows with less poundage) while the lower the Spine (thus meaning less deflection) the less flexible (more stiff) the arrow will be (for bows with more poundage)
Commercial arrows got a Spine rating on them, and based on my experiments, same Spine number doesn´t mean exact deflection on both brands.
But in 99% of cases the numbers and flex are good enough to serve our needs (most of the people is not an Olimpic gold medallist)
The intention of this contrapt