Sorry, but all AA, AAA batteries, 16 gauge wire, 1 inch pipe, 16 inches pieces of wood are equal in their specification. Steels AISI 410, 440C, API 5L grade B pipe all conform to a specification.This is a main reason to the existence of ANSI, ASTM, ISO and all standard associations.
I was thinking the LiIon batteries were headed to become a standard power source for electric devices during the time I stayed absent from the flashlight scene.
I´ve just found 1 minute ago that the “vapers” seem to use only flat top 18650s. Didn´t find out for sure!!! And lots of people ask how to solder a blob on flat tops, what is pathetic. Didn´t get the reason, but this kind of thing leads to confusion and avoids the maintenance of a standard.
I seems even the flashlight hobby forum seems to be decreasing. Very sorry.
Best Regards
Eduardo