Well, for 26 years we have kept it the same time -- the second weekend in December. I am a big believer in keeping events at the same time yearly, whenever possible.
The reasons are this is a good time of the year for wind and the water is still warm; room rates are at the lowest, just before the season starts; and the Keys are not jammed packed.
By the way, the reason for the Tradewinds on MLK weekend is that room rates are lower juste after the New Year, and for some this gives you an extra day on Monday to get back home.
Rick