Charlie,
Try sheeting in tight before putting on the downhaul. This will allow you to get more on the downhaul than you will without the mainsheet tension. Feel free to use a smaller diameter and longer line for the downhaul if that helps you get more tension. That should make a noticable difference.
So, Mike. Was this what you did at Duck?
At Duck, I had way too much pocket in my stock sail and there were too many problems for me tweak the boat, flatten the sail to my satisfaction, and feel safe in that kind of wind in order to continue. Especially with the jet skis fishing everyone out of the water.
I think it was you who said, "We got a gust of 37 mph!" on Saturday that made my jaw drop.
I was very disappointed that I missed the opportunity to continue at Duck. It was fun but it was extreme.