Hi guys...
Great to hear your getting into the most addictive sport in the world! It will take some time to learn the fundamentals and basics but once you get yourself grounded you will all have a ball, but without a ball.... If ya know what I mean..
Ive been windsurfing for as long as I can remember and have had the amazing experience of being a windsurfing instructor in the Greek Islands for a couple of summers.. The reason I explain this is that I saw many many people get themselves into quite dangerous situations because of lack of knowledge about weather and wind conditions. 99% of people who we rescued were beginners, the other 1% were people who broke equipment.
This weekend is forecast to have very strong winds. It will be very different to a clam or light breeze. It will not be pleasant and relaxing. It will more likely be hectic and VERY energy draining. Dont get me wrong - If your experienced and know what your doing then you can have the time of your life!
Dachande to put it in perspective - your 3 sail sizes. Forget the 6.4 and 7m for the weekend. It will be far too strong. I also think the 5m will be too big for your ability. I'm a 90 kg guy and I will probably be using a 5m on a small board (90ltrs). And I will also be rigging the sail to suit the wind conditions on the day, not just rigging the sail. This can make a HUGE difference!
Please dont think I'm trying to turn you guys off the sport because I'm not.

Its an amazing sport. By all means head down and check it out, but always know your limits and if a small part of your thinks its a bit fierce its probably best not to risk it and to plan your next day out with a beer or two in a pub.

Cheers
Michael
Ps. If you guys are keen to learn more about windsurfing, try to get your hand on a book called tricktionary. Its the bible of windsurfing and can teach you a lot of good techniques in everything from rigging to getting out on the water. Find it here -
http://www.tricktionary.net/