I think Matt's issue with the F18 is easy to understand: he mention his crew weight was 130kgs. How many teams at the F18 world where using the small jib and small spin? The number I've heard is None. Nada. Zero.

It is a clear indication that if your crew weight is less than 140kgs, you are not competitive in the class. And even at 140 you have to carry 10kgs of lead to qualify for the big rig.