Get a bunch of formula guys/girls together & theres always a big difference in what works and what does'nt work. I guess theres no silver bullet or magic formula. For me (107kg & 192cm), I always have the mast foot as far back as I can get it (be it 9m,11m or 11.9m), I find that I can get more drive on the fin for early planning in super light winds, also, its easier to stuff the nose off the wind to get going earlier and increases acceleration loads (not to mention faster top end). Also try increasing your harness line lengths quit a bit, again it will be easier to drive the board broad. Also try a wider footstrap setting, will make going real broad more comfy. You wont get extra drag if you try these things. Doing these things gets me going easily in around 7 to 9k with an 11m and I dont feel like I have much (if any) disadvantage with the light weight formula guys.