Regarding the bit "An empty bag blowing across the road may not be worth the disruption in your path of travel."
I don't want that plastic bag anywhere near my ST's radiator grill, so I will try to predict its path and avoid it every time if I can safely do so. These bikes need full airflow to stay cool!
Head and Eyes really does work, IF you practice and make it instinctive.
As the famous movie pilot says, "Don't think, just DO."
It must be instinctive.
Make time to practice. I take a rider training course every season, and many are free thanks to grant money from Uncle Sam to state coffers.
Check your state's highway safety office and perhaps you can find a free course in your area. We Oklahoma riders are lucky to have several to choose from.
Keep learning and improving, and ride safe!