I can really recommend the Palmer bracket. I have the standard screen, a Puig screen extender and the Palmer bracket, and it seems to get rid of the dreaded buffeting very nicely. It doesn't just allow increased air flow behind the screen (which seems to negate turbulence coming over the top of the screen) it also allows you to tilt the screen into a more acute angle, which also helps. The only downside is a little more wind hitting my shoulders, but I can cope with that much more easily than having my helmet rattling from side to side as previously.
I've done a couple of big trips with this set up and it makes a big difference at motorway speeds. Only tip is, keep checking the adjuster bolts..one of mine fell off while I was riding. I told Palmer about it and they sent another, no quibble, free of charge. So good after sales service too..
