I am about your weight (mine fluctuates between 78 and 80 kgs), and I would agree with Maximus. By trial and error, I came to the conclusion that if you do not do slalom racing in light winds, you do not need any board between a Formula and a 107. I used to have an iS 133, then I bought a Formula and an iS 122, and then an iS 111 woodcarb, and I sold the 122 because I was no longer using it. I use my Formula with TR-6 10.0 and 8.4, and if I'm on the 8.4 and the Formula and the wind picks up too much, I keep the 8.4 and go down to the 111; that board carries the 8.4 very well.
I have a friend who is a few kgs heavier than I, he is on different boards brands, but he has also reached the same conclusion, and has no board between his Starboard Formula and his Falcon 112.
My advice: keep the Formula (there's nothing like one in light winds), get the 107, and then work down from there, depending on how much wind you get on your spots. There's a BIG difference between a 111 and a 101, so I assume it would be the same between 107 and 97. If you keep the Formula and buy 3 boards, go 107, 97, 87. If you are limited by space and cannot store more than 3 boards, keep the Formula, and like Maximus advises, go for the 107 and the 90.
Formula: 9.6 and 8.6
107: 8.6, 7.8 and 7.0
97: 7.8 and 7.0
87: 7.0 and 6.2
90: 7.0 and 6.2
Last edited by ThierryP; 24th August 2010 at 08:56 AM.