RE: Putting an NP Excess 6.9 on a Kombat 97?
(sorry, the edit function doesn't work anymore to add further comments)
As for potential imbalance problems with the Kombat 86, I didn't experience any so far, providing the boom lenght is not greater than 204 cm (Jet 6.9) or 202 cm (RS1 6.6) with the freeride setup (mast-track 40-50%; all 4 straps back and outboard, stock 30 cm freeride fin set in the middle of its finbox as recommended). However, with the wave setup (mast-track 30-50%, all 3 straps front and inboard, wave onshore 23/24 cm fin set forward as recommended), I must acknowledge that pointing upwind with the Jet 6.9 sail is a bit less efficient than say with a smaller sail such as a NR 6.2. The Carve 111 still is far superior with the Jet 6.9 sail and a wave setup, even with a stock 2001 25 cm freestyle fin.