I took a chance and ordered a couple of the
"Boxer" 26650's from GV. It stated they were 67.4mm but they fit totally fine in the Stout. Measuring it showed 66.47mm... hope I'm wrong but that's the same size as the Efest green.
The first battery vaped a total of about 16 ml at around 42 watts. It looked like only one bar change away from being empty and I took it out, popped it on the charger and it read 3.5v. On the second battery now.
I sent an email to GV asking who makes the battery and if it was a rewrap... was told they're OEM'd specifically for GV. Maybe
@Mooch will have a chance to test one some day.