The sails shouldn't oversize 7m². But is the form factor discriminant (I mean, if we respect the rule of the 7m² with a 2m max boom and a 5.8m lenght of mast, are we allowed to design the form we want without any limitation ?). The question can seem stupid but it's 'cause I'm re-thinking about the ART Sails (windsurf sail from the 80's that allowed wind release when over an pressure amount you limit by some tuning).