It is a Tornado so we have good leverage. But as soon as you pull the downhaul the draft of the sail goes forward and the top bends open. This causes more induced drag. The shape of the sail is no longer optimal. The GPS shows the results. The big problem is that as soon as the gust is over you tend to sail lower to keep the windward hull up. I think that using downhaul gives the same result as opening the traveller a little bit. Still sailing somewhat lower upwind. A better solution might be more mastbend by more diamond tension. But than you loose speed and depth downwind.