At 90 kgs I ride a 100 Tabou Freestyle Pro and find that it is a nice size for me. It planes up very quickly (I use a full sail size smaller than my 95 FSW in the same wind) and it is stable in maneuvers. I typically ride a 4.7- 5.6 on it. If you are in ultra light but plane-able winds, the larger board you are looking at will work well also. I simply like riding the most maneuverable size possible given the wind strength.