AWS, what you experienced yesterday is perfectly normal, and to be expected. This little engine will get slightly smoother with more miles on it, and should be fully "broke in" when it hits 5,000 miles. As for the quality of gas that you used, the 91 octane vs the 88 octane that you had been using, it can be that, as well as the specific quality of gas from that specific load of gas that was delivered to that station. Meaning, you can get a good tank of gas, or a bad tank of gas, depending on where and when you get the gas......which affects the little engine as much or more so than the octane rating.
In 2019, it also depends on the gas that is being delivered to the area of the country where each of us live, meaning, how much Ethanol is in the gas we are buying, whether it be 5%, 10%, or up to 15%, as that too will affect the performance.
If at all possible, so that you have a straight line comparison of the quality of gas any of us are putting into the tanks of our bikes, do your best to use the same gas station every time....if possible....so you know WHERE you got the gas, and whether you end up with a good tank of gas, or a bad tank of gas.
As for engine heat, to warm you up, as you already noted, this "ain't you old Honda 750". (meant in jest)
One thing I have done with both of our Van Van's, is to install Moose Racing foam wind guards, to keep the colder wind off our hands. These can be installed in 1 minute, and removed in 30 seconds, and they work perfectly. They weigh nothing, and most likely my wife and I will leave our ON the bikes all years long, because we live north of the 45th parallel.
And, for FUN...you can change the name of the Moose Racing wind guards to MOUSE Racing....as in...small bikes.