Bigger,heavier is not always better, I think this donkey is also thinking this. I always choose to take 90% that I can handle. That is in my case:
12-25kn Fanatic Falcon 91 + Neilpryde RS:Racing 6.7
14-30kn Carbon Art Speed 50 + Neilpryde RS:Racing 6.7
20-45kn Carbon Art Speed 44 + Neilpryde RS:Racing 5.8
But these numbers are for everyone different, what sailsizes do you use???