Guys,
I gotta say from using bungy chords, I just don't use them anymore to secure sail etc. They have their uses, but I just don't trust them. Ever get whacked in the face as one snaps? Also the sun eats them up. Another thing is to stay away from plastic ends. Sun & plastic do not go well.
What I use are straps with quick connects. And, if underway, I use a personal way of ribboning my mainsail cover so I can put it on by myself even in windy conditions & still be able to tame the cover.
First, turn on the iron jib. When removing my cover, I undo the quarter turns, unclip the end fitting, then stand at the mast. I grab about 2 feet aft of the mast and with hands on both sides of the boom, pull the section forward as far as I can so it's at the mast. That's the first "ribbon" fold. I then pull the next 2 foot section on & on until I am at the end.
I then undo the front part of the cover from the mast and lay this over the ribboned folds. I put my arm under the now ribboned cover & pick it up. It will look somewhat like a saddle. I fold it in half as I stow it in my aft lazerette.
When covering, I carry it to the mast and sling it over the boom close to the back side of the mast, I attach it around the mast grab the end and walk it to the rear. Clip it on the back of the boom & do the 1/4 turn fasteners as I move forward to the mast.
Make sure of your angle to the wind, and by now motoring, go as slow as possible so you don't fight the wind.
CR