"Re the last item: the MSR instructions for the XGK stove explicitly state that priming the stove requires a 'fireball'."
That's partially true. On a high expedition, three of us were using a new XGK, and due to weather, we had to cook inside the tent vestibule. At the beginning, I had to light it each time with a pretty good flare, and I was so paranoid about burning the tent down that I had a lot of aluminum foil deployed to catch the flare. But then after a few days, I was more practiced about igniting it efficiently without so much flare, and after one week, it was nothing at all. We got so efficient that by the end of the expedition, maybe 11 days, our three-man team had used the same amount of white gas as the best two-man team with the same stove.