I have tell tails on the leach of this sail. I have never sailed a main with these before. As you state straight back and curling to the backside is right. What do they do when the set is wrong? Do they fly to the front side, up, or what? Is there a way to over travel and let out by reading these as can be done with luff tell tales? I am running a spin on this boat and really haven't had any problems with the main downwind. Upwind in light stuff I feel lost. I am sure most of my trouble is me. In a good blow I seem allright but think I am still oversheeting. I am running this sail on a comptip and the squaretop is really turning off, downhaul seems to bend the tip too much and create a funny shape. Thanks for the input.