Dan,
There is no rule that says the skipper and crew must always sit on the windward hull. To go fast the skipper and crew, the balast, should sit where ever is necessary to allow the boat to 'fly a hull'. There have been comments on this forum about A cat sailors sitting in the middle of the tramp and 'flying a hull downwind'. Look at some of the righting moment numbers in this thread and you will see that the people on the boat are the major contributors to total righting moment. To go fast the sailors should always place their weight so as to allow the boat to just barely 'fly a hull'.
Good Sailing,
Bill