Wanting to upgrade my fins (set on a thruster set-up) for my Vex Profusion 8'0 (8'0x29=115) I weight 79kg dry. I mainly use the board in larger swell 4-6/7/8ft. I was thinking Shapers S9s (5.19") but did not want to kill the board am worried that it will not be as loose. Was thinking 4.7"s rather but hard to find in futures. Any recommendations? Will the S9s work well without stiffening the board up to much? Cheers in advance.

I'm about 77kg and I generally like bigger fins, but I've never liked the S9's. I had set and hated them in every board I ever tried them in. On the other hand, I mostly surf 2-4 ft east coast slop so you would be better off taking advice from some of the WA crew.

Being from WA, you may be able to test the quobba fins? I have not fully tested them, but it looks like what you are after.

For your conditions, I am now using C-Drive fronts and standard central fin with some rake. But there a no C-drives in Future (yet?)

G'day mate, I've got the same board and have put on some Dane piolo 01's and very happy. Haven't had it out in anything as big as that but still loose and no sliding. Oh yeah, I'm 90kgs just for the record to re performance. Look good too!!