Alan: Absolutely, on the flat main and jib (don't forget the jib) in ultra lite conditions and here is the reason why. The reason is that the wind does not have enough power to get around the sail when it has any belly. The belly does not allow the wind to stay attached. With the flat main, the flow stays attached. I love racing in those conditions, especially when I see the boats in front of me with an improper sail trim set. No matter what the wind conditions, I watch the set of the sails of those in front of me - not to copy them but to determine how long a day I am are going to have. A lot of these guys, especially in the middle of the pack, don't seem to have much of an idea of what they are doing or, most importantly WHY they are doing it. If they have a very crappy set, I think to myself that it is just a matter of time before we overtake them. If they are set properly for the conditions I know it is going to be a long day. As a note, if a mate can sail in very lite to lite conditions he can sail in anything because he understands the elements of sail trim. The same applies in heavy conditions. A lot of mates allow a good deal of draft depth (belly) in those conditions and if you want to scream along that's not a bad idea but if you want to control the boat just flatten the sail. If that doesn't work, then start throwing in a reef or two.Alan, based on your initial comment regarding the flat sail in ultra lite conditions and the reason you gave, I think I'd be in for a long day if I was behind you!!!