I have a bunch of scouts coming over tomorrow to build mostly scratch kits that they designed. Most of the designs are minimum diameter bt-20 designs. I would like to use kevlar shock cords. What is the recommended way for attaching kevlar to the motor mount? Is it recommend to cut a notch in the engine block and then loop all the way around and tie a not? Or is it better to put a knot on the other side to keep it from passing through? or none of the above?