Full disclosure Steve @ K4 is a friend.

Regarding K4's and heavy chaps.
I'm 110 kg, sail (in UK) a Simmer Quantum 115 with 17cm Scorchers and 10cm Assy's.
I first tried 16's and got a bit of spin out. Swapped those for 17's and the problems went away.

Regarding feel.
In my 105 Quantum I have the Simmer fins the board came with. They look carbony, and are certainly stiff.
I find the k4's are bit like putting suspension forks on a bike.
They make the ride smoother and are more forgiving, better grip round corners.
A bike with rigid forks is more racy, more efficient. To keep speed off tarmac requires more control from the rider.

I like an easy life, I lack finesse and like the price, so I use K4's. (+ I like supporting a friend).

www.facebook.com/Starboard.Windsurfing/videos/699368550502023/?t=423

Jump to 7:00 in the video for Koster's preferred fin set up.

forceten said..

philn said..
www.facebook.com/Starboard.Windsurfing/videos/699368550502023/?t=423

Jump to 7:00 in the video for Koster's preferred fin set up.

as far as I heard Phil likes a quad, but any fin setup will work.

He said he uses them as a twin most of the time unless a very powerful wave like Mauritius or Western Australia, and then he rides it as a quad.