I have always had a tinted one on the drivers side for just that kind of thing. Works pretty well, up to a point. Added value, you can tilt it up with the top down and it works like a mini-spoiler. (Back when I had hair that mattered to me)
Mine is so old I can't recall where I got it, probably Moss or their 1969 equivalent.
The brackets clamp onto the windscreen at the top with a couple of little allen set screws and you can button the top on right over it. I never got around to buying one for the passenger's side.