4) In moderate wind, what is the basic correlation of downhaul to speed (assuming one isn't overpowered by conditions)?
You want to be specific as to what type of sails you have. I have just changed boats and went from a mylar square-top to an old pinhead design (Dart 18). I discovered that this pinhead gets FULLER when I downhaul. To depower I RELEASE the downhaul, just the opposite of the fat head.
Every boat is different, every sail is different, every sailor is different, every tack is different, every day is a new day. Whatever you try, it probably isn't the best so keep tweaking it. "Faster" is only relative to the boat beside you.
And get a bigger boat.
