Here’s a pic of S2+ with short pill/long reflector —- as you can see the S2+ head is aout 1/8” too short of accepting the battery tube completely—the S2 head is 1/8” longer —— you might be able to shorten the thread length but I’m not sure how that will affect the short tube with a 18350 cell —most of the time it’s already on the short side — you might be able to gain some by trimming/sanding the pill — both the pill and the reflector have a recessed space for the LED board
