I thought I'd contribute my impressions of aftermarket windscreens. Specifically the CalSci 'wide medium' for 2008-2014 C14's.
First some background: I have a 2012 with stock handlebars and stock seat. I'm not sure why everyone calls out their height and inseam? For me it's 6' 4" w/ 36" inseam. I think it's more valid to just say it's 26" from seat to the bottom of my chin when sitting on the bike.
Compared to the OEM screen: the CalSci wide medium is about the same overall height, but it's 1.25 higher in the middle because the stock shape dips down through the center and the CalSci goes straight across. I still look over the top in full up position (similar to the OEM screen). As for width, the wide medium is about 3" on each side wider towards the bottom and about 2" wider on each side at the top. And again, the profile is straight while the OEM curves in the middle.
Fit & finish are fine. CalSci shipped mine the same day. The only small complaint is that the CalSci screen didn't ship with a way to get the stock center screws to work. The OEM screen is .200" thick and CalSci's is .177" I had some .062" thick washers (.312" ID and .750" outer diameter), so I was able to snug the center screws that way. I later put on stainless washers with .406" ID and .750" OD. (needed the larger ID to clear the shoulder on the stock custom screw)
Performance: WOW! I get the same airflow in the down position (except it's quiet air). With the screen full up, I'm inside a really quiet pocket. There is still 'back pressure' in full up position, but I have to be going 80+ mph. I couldn't even use 'full up' with the stock screen because it just hammered my head with turbulence.
Overall, I'm very pleased with this screen.
UPDATE: I did 200 miles or so with the wife as passenger this weekend. (on a fairly windy day). Anyway, she said the backseat was calm with the screen full-up. Tailwind was best (obviously), headwind was second with crosswinds being worst.