RE: Putting an NP Excess 6.9 on a Kombat 97?
Can't say I've tried a 6.9 but my hunch is it's questionable. I generally find if you go too big a sail for the board, things can feel sluggish/bogged down. Put on the right board & you're ripping & things feel light & free.
Ideal for the Kombat is probably 5.0 to 6.0. I find a 6.5 works nice too, but smaller is better.
If you do try it, the fin size make need to be considered.
If it doesn't work out, you'll have a good sail size for your 115L.