Years ago I put National Cycle Plexistar 2 windshield on a 77CB550F I used primarily for commuting. (See avatar.)
They have changed all the marketing names of their offerings since then. It looks like the closest thing they now have is the Plexifairing GT.
Mine mounts on both the bar and the front forks, which might be a problem for the 76, as they had accordion boots over the uppers where it is best mounted.
On my 76, I used a frame mount Vetter Quicksilver. I prefer the frame mounted types for longer rides. But, would much rather have a bar mount type than nothing, particularly when speeds get up over 40-50MPH.
Much depends on where your bars are mounted and if the bike has been modified to have "cafe" bars. If such style is your forte, I think you will just have to suffer for your art.