Just to comment about the headlight/power usage having an effect on fuel economy.
While I always drive with the headlights on, while I was burping the new radiator, I figured I'm mess with the lights, while I was monitoring the temp on the Access Port.
While cycling through the assorted light settings, I watched the boost values since that should relate to economy. From the lights off, to lights on, lights on/fogs on, hi-beams on, there was a steady change in the boost value.
So power drain is definitely a thing with fuel economy.
SC