Does your weight really have anything to do with wind surfing?
I range between 68-70kgs and frequently have two thoughts:
1) Ideal weight especially for light to mid days and get up planning earlier than others so it's a plus
2) Too light on heavy days and get overpowered if not using a smaller sail than everyone else, or the wind comes up and I can't handle it if I stick to the bigger sail (which is probably smaller than what others are using).

What's your thoughts? Is it your weight or does it really come down to your technique and the range of equipment you have to suit the conditions. Do people change sails regularly when you get overpowered and have come in to change down. Do you carry a big range of sails, say more than 3? I would like to weigh say 80kgs to make things easier but beleive it or not I can't put weight on, too late anyway as I am now the big 6 0 and starting to get lighter!

Welcome your thoughts
Cheers!!!