Every arrow seletion chart I've seen until the one you referenced shows the 2016 to be way under spined for my set up. Thanks for the reference.
The bowyer that suggested 2016 did so about 21 years ago. Did I trust him? Sure, I bought the arrows. Did I understand why? Nope, but I'm working on it.
Ya I'm missing alot. But I'm working on it. Asking questions and trying to learn does not invite you to be rude and condescending.
Let me take a stab at this.
First off, my assumptions; one, you say your riser is close to center cut, so I am going to assume your rest is a baer hair shelf rest and a leather strike plate, and two, you are shooting fingers. If either of these two are wrong, it changes the physics slightly, but irrelevantly.
So if we were above you looking down at the bow drawn, you would see the center of the bow, the arrow point, and the nock form a triangle, rather than a line like a modern compound or past center cut riser. This puts your bow and string direction of travel in one direction and your arrow direction of travel in a slightly offset direction. Now, as you release with your fingers, the string starts my bong forward, but not in a straight line, its moving in a slight s curve. As the string is moving, the arrow starts moving in an s curve as well, allowing it to wrap around the riser without coming into contact, this curve around the bow is what pushes the arrow into the line established by your string, bow, and target.
A lighter than chart spine allows the arrow to wrap around the bow, if you go heavier on the spine your arrows will move farther and farther in the direction away from the riser window because of fletching contact and deflection.
This is why the old Easton charts from decades ago used to have the small print, "recurve, longbow, and finger shooters subtract 10 pounds from draw weight."
