The whole riding with/without a windscreen thing seems to be pretty subjective.
At the end of a multi-state, multi-day trip another scooter rider remarked to me "I can't believe you made that trip without a windscreen!" I was surprised at the remark because I really didn't understand then what he meant by that.
I rode for years without a windscreen on my ET4. Personally, I never found the wind to be a problem, I never found the helmet sound to be deafening, I was never bothered by buffeting at high speeds. I never really felt the need for a windscreen. Maybe I'm aerodynamic. Maybe I'm just numb.
Well, I eventually bought one. A flyscreen. I didn't buy it for the wind...I just liked the looks, and it gave me an extra surface for stickers.
But I'm quite happy with it. It helps keep the wind off my chest (I'm 5'-9-1/2"), it doesn't blow air up my helmet, it doesn't impede my vision in the rain, and it isn't so big as to cause "sailing" in wind...which I
know would be a problem on some of the bridges I cross during my commute.
I'm also able to commute more comfortably in colder weather, too. I'm betting if I had that flyscreen on the scooter when I rode the Blue Ridge Parkway, I might have saved myself some teeth-chattering at the higher elevations on that rainy day.
Bigger is not necessarily better. The flyscreen does it for me.