grezac34 ok, well I would say:
7.3 - 12-18knots
6.2 - 15-22 knots
5.3 - 18-25knots, this really depends on how overpowered you can/like to sail. For a true 30knots wind you need a smaller sail in my opinion?
there will always be some overlaps and it really does depend on your pumping skills/active pumping? I would still go for bigger gaps with 5/6.2/7.8 to be honest?