There are countless threads on Clean air, Dirty air, "Do I need Sanchos", "Do I need a taller Windshield"...
I've found a true test that will let you know if you have found the perfect combination for YOU and YOUR Bike..
Last night on my drive home while on the highway riding somewhere between 60-70 mph I had to fart - Couldn't hold it..
About 10 seconds later the stench was still floating around me.... wouldn't go away...... At that moment I realized I had the perfect air deflection combination.!
Disclaimer : Results may vary depending on what you had for lunch.