In a strong wind, if you fly for a while, the fabric on your sail will stretch a bit. Sorta like the stretch in the sail I sent you. But after a couple hours it tightens back up and the sail is flat again. After a ton of flying in strong winds, the stretch will stay. None of my kites are stretched yet, and I fly a lot.
If you tried to fly the rev with the top lines only, it would just flop around. It's not until you apply some brake, to get the sail trimmed right, that you get lift. Adding more brake slows the kite down.
But that's no fun. I say pedal to the metal. Learn to zoom.