RE: kombat 97 fin sizes
Perhaps I should have worded my reply better.
What I meant was, to play more with his set up before just rushing out and buying a new fin$$. The K's are very versitile boards and have plenty of tunable aspects. Seeing the user was wanting a try a freeride sail heading towards the upper limits of the board design and has not mentioned spin out, I was just suggesting he first try with straps and fin/mast track placement and drive the board harder.
Once these are exhausted then sure try a bigger fin. But if he has a good cash flow then just go ahead and by a fin - just hope he is sure that he knows for what he is buying it for - waves or freeride.
The advice you have given Floyd is sound and will be obviously helpful. My advice was based on K95 use (i'm 85kg).