Noctigon KR1 which 18350 battery?

Actually your reply is not completely accurate, and it may misleading concerning the 18350s for the Noctigon KR1.

This is Hank Wang’s (the maker of Noctigon flashlights) reply concerning the use of protected or unprotected 18350 batteries:

HOWEVER:
The OP on that thread said that the orbtronic fit, with a slight modification, in this case, not using the lanyard ring in the flashlight.
Check: KR1 won't turn on.

As for the suggestion, Vapcell is, indeed, probably one of the best solutions, currently!