Thanks for the extra info.
Those washers definitely make a difference! I've been thinking that it would be easier to go for a smaller screen as I know that would definitely work. There's no guarantee a longer screen would push the wind over my helmet, or at least my ears, but after years of...
I'm not quite sure I understand how this has increased it by the 3-4 cms you mention in your later post. Surely this pushes the bottom of the screen out which would push the top backwards and therefore down.
I don't suppose you have a picture to show what you did?
The noise and buffeting is...