DH,
I can answer most of your questions now.
1) Yes, it is INFINATELY adjustable
2 & 3) Its adjusted manually. Here, you have to pull the outer shield off by removing the "T" screws and lessening the allen screws on the brackets however, you can leave them semi-tight and reposition the shield but if they're too loose, the wind force will do that for you.
4) The twin shields acts like a slat system on the leading edge of an aircraft wing. The outer shield acts like anyother shield in deflecting the air up. The flaw with conventional shields is that with the air traveling at high speed across the front of the shield and no air traveling behind it, you have low pressure behind the shield trying to suck the fast moving air into the low pressure area...where your head is. This is referred to the burbble effect where the air swirls...you can see this on a humid day with condensation swirling off an air craft's wing when it has a high angle of attack (climbing steeply).
Your BSR may even complain of being smacked in the back of the helmet with air...this is the burbbling air trying to fill that low pressure area...you may be just fine while your BSR is miserable. Kuryakyn even makes a Airmaster Airfoil that mounts behind your BSR to diswade this burbbling (see pic)
The gap between the two shields allows air to be scooped and directed up between the shields. If setup right, the that gap air will be squeezed in between the two shields with a venturi effect which actually increased the velocity of the gap air over the air in front of the outer shield. This would reverse the burbble and kick the air away, up and over your noggin.