RE: kombat 97 fin sizes
I'm 85 kg & sail 6.5 retro with K96 on a 30cm Gsport freeride fin. At least average upwind abiility. This is typically 15-20 knots free-ride considitions. I've sailed this rig in 20-25 knots & upwind of course gets even better.
Floyd, you're 10kg heavier so I'd expect this would can things abit. I agree the 32 cm size would be the natural fit for 6.2. Like you, I was concerned with fin box stress so got the 30cm instead of 32cm.
Consider also the shape of the fin, not just size. Perhaps if upwaind is important, you may want to look at a more pointer style fin.
- this is where I got my fin from
- good articles on upwind technique