1.
Given that I currently have a standard BLF GT, and a second one with exactly the same driver and led, but using a 120mm aspheric lens, and getting more throw out of it (1.3 vs 1.5mcd), I think there is more to it than “reflectors are better than lenses”. No wavien collar installed (yet).
Enderman himself has used lenses for a lot of his lights, and has had to stop because getting bigger lenses was getting impossible.
2.
Adding more emitters to increase throw forces you to have a bigger head regardless. If you try to cram more emitters in the same space, you have to get by with smaller reflectors/lenses for each emitter, which will decrease the focus/increase the spill/increase the angle of the beam.
3.
“In theory, using multiple emitters is often the best answer for the longest throw / size.” No it isn’t. It literally isn’t.
Just look at the list of the best throwers Most Powerful Flashlights in the World (by throw distance)
Or even direct examples. The TN42 uses a single led+reflector on a 100mm bezel, 2000 lumens, and claims 1550 meters of throw. The TN40S uses 4 leds, the same 100mm bezel, 4450 lumens, and claims 1150 meters of throw. The XP-L HI emitters used on the TN40S even have higher cd/mm die than the XHP35 HI used on the TN42.
If you increase the throw by adding multiple emitters and running them all hard and increasing reflector size, you are not getting more throw because multiple emitters are better for throw. You are getting more throw because you have a using more power on a bigger light.