Hello Bought a Givi S180T shield cost £100 2 years ago for my 650 worked excellent for directing the wind but had to take it off due to the bloody alloy adjusting block right below your vision, very distracting so go for one that's mounted on the two ends. The best option I have found on two 650 Stroms and the 1000xt I have now is the givi D3105ST for the 1000 and the equivalent style but different part no for the 650.
Having had 3 new vstroms I think its bad at 6 foot tall that the std screens supplied in any position make more noise, than my 1200 bandit sitting at 130mph unfaired. When I bought the 1000xt last year in any height or any of the 3 position made no difference until I fitted the D3105ST now PERFECT, even on the autobahns in Germany sitting at 115mph from Poland to uk in a day. These bloody Japs at three foot F*** All need to supply bikes to Europe where more people are over 6 ft need taller screens or don't supply a screen at all reduce the price of the screen so we can sort out which screen, because you will have to any way.
So try the extension or go the givi taller screen.