Windshield

If you want true protection from the wind and limited buffeting you need a full fairing like offered on full size touring bikes.
The full size Batwing fairing on my HD Electraglide stops 90 percent of the wind , They are offered in the aftermarket and will fit most bikes
My bike also has the lower fairings and that completes the protection .
I can use lower windshields to let in more wind in the Summer , or use the standard height shield in the cold or on long trips to reduce fatigue.
I gave up a long time ago trying to make my LTD a touring long distance cruiser but the bigger and wider the windshield the better for protection
Dave

Buffeting can usually be addressed by changing the angle of attack on the windscreen (if adjustable), as far as choice, I'd say go for the national. They are US made and have a great warranty from what I've read and they've got the ultimate selection of different styles. Personally I'm rocking the Plexistar 2. not quite a full fairing but gets the job done well.

I'm with you Dave, If I decided to start doing real long distance trips it will probably be on a Road King.
Prices are coming way down

Still there are days I wish I had some wind protection for the Kz

My wife has a National on her bike and it works well