I have the Plexi2 as well, but I really hate the buffeting I get at the top of my helmet at higher speeds. With earplugs in to block wind noise, it sounds as if someone is shaking my head like a maraca. Have tried many different angle and height adjustments. Might be the helmet too. But frankly, as I have a Protac backrest keeping me in place, I'd rather ride without the screen.
That is the biggest problem with adding a windscreen. My first windscreen was a Memphis Shades "Hellcat" that took quite a bit of adjustments to get it to work well.
I then went to the Plexi 2 also and went through the same issues, luckily for me the screen was cut down 3-4 inches when I bought it. I then after getting a lower seat (Corbin) I lowered the headlight an inch and repositioned the screen back but not down some. This seemed to kill off any trace of helmet buffeting.
The problem with screens on cruisers seems to be the "layed back" ergos of the bike put your head so far behind the screen that you can't seem to get into that "cone of silence" unless you lean forward.
The size of the rider then can make a world of differnce. As does the type of windscreen used and how it is positioned. This all can be alot of voodo to deal with cause there is no exact measurement or guide to go by in getting a shield set up right.
Part of the issue seems to be the flow of air coming behind the screen. Apparently if there is too much it can be a problem, and if there is not enough it can be a problem too. As I mentioned, I lowered the headlight and that seemed to help. If you look at the side by side photo here:
You can see the space between the screen and the headlight actualy got bigger when I lowered the headlight. I think this allowed more air to flow up behind the screen and helped with the helmet buffeting.
I have seen windscreens for some bikes that have holes iin them. Not big enought to negate having a windscreen in the first place, but just large enough to let some oncoming air flow up behind the shield. Here's a photo of of one being compared to a stock screen on a Moto Guzzi :
You can see the T shaped hole in the middle of the screen. It might be worth the effort to try something like this with you PS2 if all else seems to be not working.