Learning a lot from your videos! I am shooting a recurve. The only point of disagreement is that you can have to stiff an arrow. Starting with a slightly weak arrow with the arrow , rest and sight at true center, shoot a pencil line at 15 yards. The distance that weak arrow is from the line determines the appropriate cut which is half that measurement. The result is an arrow customized to the bow poundage, actual draw length of the shooter. The spine will be specific to the line of force the bow takes. Spine is an impediment to form. Please do not divulge this to many people as I have sent this and more to CX and is inproduct development. It’s physics. Thanks for the videos! Please try this.