Some follow up from my saga last year at this time. I found some longer screws at a small hardware store - they were cheap enough so I bought 3 different lengths...all longer than stock and several small washers for spacers, all in stainless steel.
They had enough length to really grip and I also used the rubber strip between the clamp and the fork to grab. So far, one season with them on and no problems.

To get back to the original issue question - they do seem to help cut down on buffeting. I have Baker air wings AND the Clearview windshield that's 3 inches taller and maybe 2 inches wider than stock.
I'm pleased right now but I would have probably bought the Memphis Shades fork deflectors instead.
On another plus side, I had to go over to Jim's heated garage last winter and test out the longer screws with the clamps on his forks, then once we determined it would work on my bike, we commenced to drinking and smoking cigars - so it worked out alright.
