I used Vector Canefire 39 and 43 on my 107 Isonic with 7.8 sail and TR7 8.4xt
I like the 43 better with both sails i felt the 39 was to small for the 7.8 in a light wind 16 to 18 Knts, it could be better when the wind pickup over 20 some knots to go with smaller fin.
I forget to mention that you recommend the Vector fin for me about 5 month ago,
I like the 36 Volt to on my Isonic 90 with TR6 7.0.
Good Sailing Dani.