I just rec'd my +4+3, std. countour. I'm 6'2", 32" inseam, heli risers, Russell seat.
I also have a homemade tuning block.
+4+2 w/ flip always had turbulence. I cut 2" off but still not smooth air.
Std. countour still does not provide a "cone of silence", but :
Lowest position: stream of air on helmet, I can feel the air on my chest (this will really help with the cool-vest in the heat.
1/2 up: Shoei vents really working. No buffet, even when turning head slightly.
Full up: Slight wind noise, will still require ear-plugs. If I "scrunch" down about 2", its silent.
All tests done at various speeds from 30 mph to 80 mph (on my private test track, of course).
I've yet to take the Heli spacer out and try it to see if that riding position would put my head in the "silent" area, however, the risers take the pressure off my "old" wrists.
Conclusion: For me, the std. countour is the answer. Another 2 " vertical height might help, but gee whiz, that'd be a monster. I might take one of the stock windshields I have in a box and make my own "Laminar Extension" to see if that helps.