In the <sail> section, you can add a <HeelCoef> tag, which will act as a heel coefficient for each sail. The default value is 1. Each sail still uses the heel file, but with a coefficient. You can understand it as a coefficient of the sail's capacity to generate heel.
There is also the possibility to add a <IsVisible> tag at <sail> level, but I have no idea what it does
Also, you can specify the duration of each action like hauling genoa, etc, and also how much the boat will deccelerate during this action. See here
http://www.virtual-winds.com/forum/inde ... ntry131141