Length
There is only one way to do it Mike. Get out your tape measure and measure the sail, boom etc. I recently added a second reef point to my main. I measured the distance from the boom to the reef point, back to the boom, along the boom to the mast, up to the reef point, back down to the deck, then back to the cockpit. Then add a foot for the knot around the boom and add 4 to 6 more feet. Remember, you can always cut it off. Good luck.
