It really depends on the wind strength. When the wind is light, weight forward to reduce wetted surface and reduce the drag of the wide stern of a 36.7. As you near hull speed crew weight should move aft. In heavy air downwind as much crew weight aft and and windward as possible to keep flow over the rudder for control.
After the the warning gun shifting sails, stuff below etc is forbidden outside of the normal movement for sail changes etc. Races that allow water ballasted boats or canting keels provide an exception to the rules of racing regarding moveable ballast.