I have to admit, Joe_Windsurfer, that I would immediately put you in the group of 'wannabe know-it-alls". As a woman, you don't know how many times folks are trying to get me to rig my sails differently than what my rigging guides say. When I hear folks talk about rigging outside recommendations being 'personnal preference', I have to think to myself, 'yeah, if you PREFER to be slow, or if you PREFER to sail with an unbalanced rig'.
The sail makers want you to be happy with your sails, and give the best guidelines possible. I'll give you that they don't give guidance on rigging on a mast that has a different bend than that recommended. But, beyond that, why would you want to go against their guidelines?
Sorry, but this is my big pet peeve.
Eric, I agree that the difference between depowering a sail by using more downhaul or more outhaul is kindy fuzzy. If you're at max outhaul, but not max downhaul, for example, increase the downhaul. I'm interested to see what folks say. There are some things that can be a little counter productive. When you pull on the outhaul to depower the sail, by making the 'pocket' less, you also tighten the trailing edge of the sail. This moves the center of effort, or pull of the sail, up a little. Not a good thing when you're overpowered. I tend to do a little of both.