maybe this helps a little bit, I sail the 101 till appr. 26 knots with a 7.2 NP RSSlalom and a 40cm Drake fin, above 26kn with the 36 cm fin and 6.3 sail. Boom in the middle so quite low otherwise there is to much pressure on your back foot and to little on your front foot, straps outside and in the last position. This works really fine, without spinouts. I guess you really need some speed for the fin to deal with the pressure. So my findings with the isonics (i also own a 122) is to use bigger fins then your used to as it will make them run more free and make them faster. I am 1.94 m and 94 kg.