A quick follow-up on my inverted mounting for this cheap screen. The position I have now (in the above photos) works best from all positions that I have tried. At the height and angle I have right now, for my height, the air stream from above the screen is smooth and above my shoulders but below my ears. I get the most protection this way, without extra turbulence. There is actually less wind and turbulence on my arms too.
Rode 70 fast highway miles this way today, so good enough sample.
It works very well and I can duck in a position where my chin is below the screen, while the top of my helmet is above it. This is nice, but of course not a position I'd want to hold for too long.
A shorter/smaller person could use this as a touring screen and get protection riding upright (I can't, I'm too tall and have to duck for highway travel).
But, there is a problem. At speeds above 65mph, the screen begins to vibrate too much. I am afraid it will destroy the screen or loosen it. Too much vibration. 65mph and under it is fine. If there is a way to tie the bottom of the screen to the turn signals or the headlight, or to install support brackets for the bottom, it will work. Alternatively, it may be possible to trim the bottom (what used to be the top) a bit to better balance the screen (there is more screen below the mounts than above it when mounted this way).