Just back from a 1500 mile trip to France. Had the Powerbronze touring screen with the Small Givi extender on. Result - if no cross-winds, absolutely brilliant. Listening to music through Sena SN5 bluetooth in Shark Evoline 3(generally faceshield up, visor down) clear up to 80mph, listenable to 100mph. If crosswinds present, reduces to 60mph for clear, 70mph for listenable. I'm 5'11, 32in inseam.
HOWEVER... riding in 39 degree centigrade heat, I would have sacrificed noise for a bit of wind flow! Still, not generally a problem in the UK!