I went thru 6-or so on my B.... Each one did something nicer than the other.......
The only one who can answer this is YOU...
My suggestion would be to:
1. Look at seats first
2. Adjust handlebars second
3. Windshield third
Ditto - copy that - and add ride with the windshield for awhile - you may like it.
I just bought and installed the F4 and love it. I'm 5'7" and went with the 11" clear vented model.