Last weekend I made a field expediant bungie collapsible PC with a large rubber band through the bridle and tacked to the apex of the PC. I could see under canopy that it was working well. Big difference on landing,longer swoop and softer in no wind. Several jumps later I noticed my approach speed had dropped on landing and I had lost some flair, sure enough, my rubber band broke. So I know that it made quite a difference.Thats on a tri 160 loaded at 1.3.