I know that people always have questions about screens so I thought I'd share what little insight I have.
I bought my bike used, and it came with the Powerbronze touring screen
. I rode all last season with it on the lowest setting, and it would direct air directly into my face (I'm 6'2" with a 33" inseam, you do the math
). At the beginning of this season, I moved it to it's highest position. The difference was quite noticeable, as the air was directed to the very top of my helmet. I found that city speeds were quieter, but highway\freeway speeds caused my head to vibrate like crazy. Slouching seemed to alleviate this problem.
Today, I received the stock screen that I bought from powerm (thanks again), and installed it on my bike at the lowest position. Right now I find that the air hits me dead centre in the chest. The ride is much, much quieter. I only spent a couple minutes on the freeway, but I currently prefer the stocker to the Powerbronze. I'll do more extensive testing this week, in order to get a better sense of it at higher speeds.
Also, I think the stocker looks better, but that's me.
I hope this helps those that need it.