Trustfire G02 pistol light, IR led, and 16340 questions

Anybody every used the Trustfire G02 pistol light?

My buddy wants me to build him an IR pistol light to use with his night vision. The G02 uses CR123a and 16340 batteries. As it is a pistol light, I don’t need to push the emitter hard as it’ll be 30 yards or less.

If anybody has used this light, what size pcb is used for the LED? Hopefully 16mm so I can use the Bergquist PCB ground down to 16mm. I’d be using a Oslon Black IR emitter, just gotta figure out which one. I’d like him to be able to use both CR123a and 16340 batteries, so I’d only run the emitter at 500-700ma with a single mode driver. The Black IR 4715S has a FV of 3.0v and the 4715 is 1.5v so I’d likely have to use the plain 4715 to keep the FV low enough to use the CR123a batteries. What drivers could I use that would handle both batteries. I’m guessing it’d have to have no low voltage shut off for the CR123a batteries which means it’d have to be protected 16340’s. Problem with that is it lists the maximum battery length for the light at 34mm and most protected 16340’s are over that.

Any suggestions or ideas?