In 8 to 20 knots you can use your formula all the time. Anyway you can have more fun on a smaller board in + 16 knots. For the widest possible two board range the iSonic 111 actually has a tail width of almost 50 cm (similar to that of a Futura 133 though the Futura is wider in the middle). It will plane nicely and be very speedy with your 9.0 or 7.8 sails when the wind gets higher. On the rare days of +20 knots wind it will be better than the 122. I see heavy formula sailors dropping directly from a F162 to iSonic 101 without a problem.