RE: F160 with smaller sail (10m2)
I'm on a 160 and somewhat your size (190cm/95kg) and find that I am not getting on anything like a 10 or smaller unless it consistently blows more than 10 m/s. I'm using Gaastra Vapors. Most formula 10's or 9.8's or 9.5's are made as highwind sails, and thus very flat and well releasing, but also with little grunt for their size. I tend to use my 11 from 6/7 to 10/11 m/s and 12 below that. With my small fw sail I'm hardly getting up on a plane in the wind range you describe (but then again I can switch down to a 5.5 once it's too big).
If you are set on staying close to 10m2 with the 160 you should definately look for a gruntier freerace type sail of the two-camber variety used in Formula Experience. Check out the NP V8 (or maybe RS Slalom?), Severne (is it C2?), MauiSails MS2, maybe the new Gaastra GTX etc. Those sails carry more bottom end for their size, and won't overpower in the wind range your're looking at either. Also they work better with 75% masts which are a lot cheaper and less fragile.
It's worth noting that I'm not only talking formula racing here. If I'm just out freesailing I use the 11 as long as the wind is below 10 m/s; the high wind sails don't seem to offer the useful range that most 11m2's seem to have these days.
Btw. I find that there is a notable difference in handling between my 11 and 12. The 12 is a wonderful sail for sure, but sail flips/jibes and stuff is just a little harder than with the 11. It might be more of a design thing than a size thing, as I believe the 12 is slightly softer to gain low-end (but thus also gets a tad "mushy"). On the other hand I do not find that my 9,5 handles a whole lot easier than my 11 really.