I've been wondering if micro vortex generators would help the cause, either a row of them at the bottom of the screen or a row on the top of the screen. The idea is to... (you're better off looking at
this , or
this, than have me try and explain it to ya)
I guess it's time to hack up some more plastic, whip out the double sided tape, and MacGyver me some MVG's to try it out.
OK, testing done, ended up using rubber furniture buffers... the kind that look like chocolate blocks... 12mm x 12mm x 5mm, set along the rear edge of fairing and screen at ~30mm spacing.
Result:- the layer of air that hits the rider is diffused more so than before. The "hard" layer of turbulent air, the point where you can feel it on gloved fingers, gets softened and lifted about 10-15cm (at the rider, speeds around 80-100kmh). With the cut down screen, there is noticeably less blast on the upper body. With the stock screen, there is change but it still means that the blast hits the lower helmet area... so it's still damn noisy.
So, it could help if your satisfaction is marginal with your existing screen.