I had a IS133, Great board, not the best gyber but it works nice with sails from 5 to 10 mts...... I'm 95 kg and 1,75 mt. The little fin from 5 to 6,7 from there the big one. And for 10 mts I was using a Select elite 52 cm. With this fin and Nitro 3 9,8 I was able to plane from 10 knots.
Fast board and strange with the mast almost in the front of the board. Not a sinker for me.