Congrats! You have the best bike ever made. (Biased. see my signature.)
I’ve systematically tried Regular (85 or 87), mid grade (88 or 89), premium (91 or 93), and non-ethanol premium, and octane has had no measurable effect in performance or mileage over the past 4 years / 47,000 miles on my bike.
In my experience, speed, headwinds, load, altitude and temperature have the biggest effect on mileage and performance in that order. I’ve gotten as low as ~30 mpg (85 mph, fully loaded, into a headwind) and as high as 70 mpg on a steady 45 mph commute with all the lights green on the way to work in the AM.