So I got another pot, the Evernew Ti 1.3L. It's larger than needed for one person but it was a perfect size for popping popcorn. I took it on a trip and was pretty sure I used less fuel than with the Heineken can. So when I got I home I did some tests. And the Evernew pot, with it's larger diameter, proved to be significantly more fuel efficient, at least at room temperature and zero wind conditions. I added a foam insulating lid that weighed ~10g (compared to the ~40g stock lid) and squeezed out a bit more.
The lessons I learned are not newsworthy to the informed. All else being equal, a pot that has a larger diameter is more fuel efficient. And, up to a point, it is more fuel efficient to turn the stove output down, down, down. Of course in the field, where thermal loss is larger, that "point" will be different.
Anyway, for your entertainment and possible edification, here are the data.
The dashed lines indicate boil times.
