I'm in the early thinking stages of a build to haul an M5 so this is very relevant to me.
The KDE 4215XF-465 motors look great on paper, but reading your build results here I wonder if I would be better off with T-Motor U7s. Thinking of an X8 build, eventually. Or I may just punt it and buy an ALTA...
Anyway, from the specs, the 4215XF motors have amazing efficiency. I'm thinking the build I want would be around 12kg all up. So, a little over 1.5 kg/motor. With X8 efficiency losses and real world flying it looks like these 4215 motors with 15 x 5 folders would only be pulling 10-15A at 6s and never be even close to full throttle.
So what was your real world view on these? Looks like you were hauling the same weight I'm thinking of, give or take, but on a hex. Were you running 16 inch props? KDE's specs claim you could haul your weight with these motors and not even pull 20A per motor.
Seems like you found the specs to be optimistic (or just wrong). If you don't mind I would love to know the details of current demand, etc.