The next time I forget to let off the downhaul DURING the downwind leg I'm sure I'm going to remember that less draft/camber = more speed.
I've only just got into the habit of letting off the downhaul prior to the windward mark so as not to overstretch the luff whilst easing the main and traveller.
Oh well I might as well use one of John Pierce's famous quotes;
"The mainsail doesn't know you're going downwind!"