On wind protection: I am a little over 6'1", 32" inseam. My seat is set to the high position. I use two screens and two helmets. Primary set-up is stock screen in low postion with an Arai XD-3. All the wind blast comes in at face level, which is just fine, since max airflow is my goal when it is 70F and up. The stock screen in full up and the XD-3 are incompatable - the buffeting/low frequency drumming at the visor/top of helmet makes me insane in under five minutes. Also, Shoei Neotech with the stock screen full up suffers from low frequency vibration/drumming at the very top of the helmet - no good. ZTechnic Tall screen in full up is ok with the XD-3, and yet again a tad bit better with the Neotech, though there still is a bit of the low frequency rumble at the very top of the helmet. I have not yet found nirvana in regards to the buffeting at the top of the helmet.
Seat: I don't mind the stock seat, though my Sweetie uses her Russell DayLong pillion. If I wear my LD Comfort underpants I can ride the stock seat all day.
2-up: The GS Adventure rocks. My wife (same person as my Sweetie!
) complained of limited leg room with the stock seat, but once we went to a RDL for her, since it sits higher by about 1.5", no more leg room complaints.