I am not sure if this is the right category, Please excuse me
I have several avid bow hunter's " one's with training wheels on their bows"

that I know who are bringing me deer legs before they take their kill to the processor. I have only used sinew for arrows and stitching, and I am wanting to learn to sinew back a bow.
My question is, how many Deer legs would it take to process enough sinew to back an average size bow?