It looks very period and as you say, should prevent a lot of the slipstream drips off the cowl.
The only caveat I would add is to read the Rain-X stuff first, because some of it isn't recommended for visor plastics, but for glass windscreens.
I have the H-D screen on the 'Glide cut at just the same point, so I have the option of hunkering down behind it or sitting straighter and looking into the breeze.
