I am 6'5" and 240. I have tried a number of Screens, and also have a Cal sci XXL.
It does a great job of reducing noise and buffeting. Great in the wet cold weather here
What I have found I prefer, after a great deal of expermenting ,is a cut down stock screen that the top is as high as the 2nd hole from the top of the screen bracket!!! I have put @ 10,000 miles on this summer with this set-up.
The only time I prefer the larger screen is in the rain, so it has been off the bike since early sping, and will not go back on unless I plan a long trip in the cold and wet.
The cut down screen puts the wind in my chest , so my helmet is in quiet air. With our height, normal screens are going to put the turbulance right in your face. So , for me either high enough, as the XXL Calsci to put the turbulance over the head, or very short.
My preference for day to day riding----very short!!