Okay, I've read many, many complaints about this issue, and I think I have an idea that could help. No, I don't mean wind deflectors on the sides of the windshield, sidescreens, or any of the other similar ideas that have made some (or no) improvements.
My thinking is this (and I invite the input of aeronautical engineers, brain scientists and assorted rocket surgeons to help out here...) - the air coming up to the windshield is forced almost to a relative stop (relative to the car, that is...), creating a very high pressure zone. The air directly behind the windshield is a relative vacuum (or, at least, a very low-pressure zone). As we all know, nature abhors a vacuum, and so the high-pressure air in front of the windshield is in an awful, burning, headlong hurry to rush around the sides of the windshield to fill in the relative vacuum behind. Result - air pounding the sides of your head, as it's in the way of this high velocity vacuum-filling.
Now, then - suppose we came up with a way to allow the high-pressure air in front of the windshield to meet the low-pressure air behind the windshield, and have the two travel up & over the top of the windshield in harmony (at more-or-less the same speed). I believe the term, in science-speak, is "laminar flow". My feeling is that simply raising the bottom of the windshield off the scuttle wouldn't work - you'd get air shooting under the windscreen, and still have a pile-up of high pressure air in front (and still the relative vacuum behind), as nothing is inducing the air to travel in a laminar flow up & over the screen.
I'm thinking of something like ducts at the base of the front of the windshield, ducted through the scuttle (under the windshield) to blow upward on the inside of the windshield (like defroster ducts, sort of), to create a high-speed flow of air UP the back of the windshield. If this works, the air coming past the sides of the windshield will simply be passing by, without charging in at the side of your head.
By way of illustration, I got a Cee Bailey windshield for my 1000 cc Kawasaki Concours. The original one produced monstrous buffeting, even when wearing a helmet. The new windscreen has a small NACA duct near the base, and ducts air in to the back of the windscreen. Prodigious amounts of high-velocity air come through the duct, up the inside of the windshield, and carry the entire flow up & over my head in an apparent "laminar flow", leaving a fairly large area of relative calm behind the windscreen, around my head. Of course, in a Locost, there would have to be several ducts, but it should work. And it needn't add any weight.