I am still using my 2014 to 2016, home made wristlights and headlamps, which were based on 2s18650, dimming buckpuck700, old fashioned cpu heat sinks, avid heat sink for bezel, AR glass, epoxy, zinc dust, thermal epoxy, 31mm aluminum reflectors that are thermally glued to the pcb to help suck heat out, elastic, wires, and a 4000 Kelvin xpl v6. Open bezel design but water proofed by epoxy. The buckpuck (92% efficiency unlike 70% in linear drivers, and not overdriving my led above .1C for a target workday) is water proof, but by battery compartment is only drizzle proofed. I carry them around in metal candy tins, inside a large book bag, else hard tool box, depending on the job. Unfortunately, I do not see any getting more efficient or and higher energy density since the 2015 xpl v6. I use a fleet of these daily for 10 hours straight, and 2 cells get me 4000 lux for 9.5 hours straight, 376 lumens and no dimming.
I have been waiting for something to get better , before investing in anything else. (Occasionally, I get bored and have made impulse buys, and have always thrown out the underperforming factory made lights that I just bought. ) I have bought and destroyed several right angle, single cell, edc lights that could run for 2.5 to 3. 5 hours-useful in a pinch and more water proof than I can make. But though they had more lumens, they were dimmer, lower lux and not cc, despite claims.
I tried to reach out to Lyten but they have not gotten back. I would build more lights if I could get any technology improvement.
My bet is that they are only interested in selling in bulk.