'Normal' speed
"...Visor down is required at any reasonable speed, at least with my Arai Viper...." I would have to add that if you proceed at "70 ish" on the autioroutes here you will be amongst the old grannies, racing cyclists, caravans and probably a few horse drawn buggies. A slight exageration but it is really HARD work if you stay in the 'slow lane.' A normal GS with a rider of about 6' height should be able to cruise quietly and comfortably at an indicated 80 - 90 mph. Of course 80 (130 kph) is the limit, but allowing for speedo error you will find that around 85 will keep you on the outer lane, not overtaking all the time, and keeping an eye out for the odd car or bike coming up faster behind you.