I just measured my foot in bootie, marked the hull with a pencil and drilled the two 1/4 in. holes for the stainless steel screws. I put large (1") fender washers on the inside of the hull for support of the lock nut on the back side and a smaller washer on the outside to support the strap. My straps are velcro adjustable. I also put some silicon goop in and around the holes under the straps to prevent leaks.