I used to agonize over this and was scared to death of breaking my boat. A friend with an Islander Bahama 30 would regularly kick the butt of my Pearson 30, something that just shouldn't happen. I was reading an article on rig tuning that said the if a big ultralight with a hydraulic backstay doesn't bend how much damage do you think that you and an end wrench can do. I reefed down as much as I could on the backstay and picked up at least a full knot. That was about 25 years ago. I just saw the Pearson this afternoon and she's still straight.