I have a long torso which has my helmet out in the breeze when riding even though I'm only 5'10". Today I installed a windscreen spoiler I found on Ebay
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&Item=221708071924 Shop around if you are interested as you can find them a little cheaper than the $40 I paid (as I found out later). Delivery was fairly quick just over a week. Its adjustable for height and angle, check out the pics. It also comes in black but I like the plain aluminum, it looks fine. I haven't tried every angle and height yet but it seems to work as advertised. The screws are fiddly to start when attaching the spoiler to the provided bracket, took some time but they eventually will thread in.
Yesterday I added some white reflective tape to the rear and sides of the luggage for more visibility. Less than $10 at Harbor Freight.