When protecting stuff from the weather a plastic tarp does not always have the grommet holes where you want them. I solve this problem by taking an old golf ball and holding it under tarp where I need a tie down. Twist the tarp around the golf ball and hook one end of a Bungee under the ball.This way you can customize the tie downs exactly where you want them with out damaging the tarp.
Bill Johnson
Costa Mesa, CA