I am not quite clear on the mainsail leech telltales. With the middle of the main telltale set as the basic trim indicator, then they seem to be twist indicators. Correct? But - as there is only one telltale at each location – does the manner in which the leach telltales flap indicate whether the sail is over or under twisted for the conditions? Please consider my sketch – assume the black lines represent a properly trimmed sail, and the red an over twisted sail. Then the green telltales in the middle should be streaming, and the blue flapping. Additionally, for the picture, the gray lines represent an under twisted sail with too tight a leech. My main question – what is the difference in the behavior of the leech telltales top and bottom from the red to the gray sail? Presumably, for the black, correctly trimmed sail, the all stream aft.