rideandfly, I have a stock screen but use the Bruudt windshield adjuster. Hardly visible but allows me to move windshield up and down to suit airflow coming onto me. I too average anywhere between 60 and 69 mpg as long as I'm not consistently ridding in the high 70's or mid 80's
For the Fly By I just took my top case and had a change of clothes in it. For the BMW Fingerlakes Rally it'll be four days I'll put my Blaze Saddlebags on. Mileage with drop a little when those are added. I just put a Corbin on and I love it. I'm a fan of hard wide seats. Works good for me.
My screen doesn't interfere with my Storm handguards at all no matter what position the shield is in. Maybe because of the Bruudt?
Nate (riding buddy who has 2013 CB 500 X) really rode the wheels off at MPFB. Hot as all get out maybe I lost a few pounds I dunno but it was hot and humid bike performed well in all conditions.