Lii-500 and C4 are comparable in slot size. You could try out the new revisions of MiBoxer’s C4-12 and C8 (the one with 8 slots). MiBoxer recently announced them to be compatible even with protected 20700/21700 cells.
4200 lumen from this size light is quite a feat. Most stick to around 3000-3500 due to heat build up. I wonder if this light will live up to it’s specs.
Those LiitoKala Lii-40A do look great for a 15A continous cell. Cheap too, at $5 each.
The UI on this light looks pretty wild. I wonder if they have tested it in actual use? The brightness levels seem good, but press and hold to turn off does not look appealing to me at all.
Count me interested, though. Maybe they will change the UI.
Dbl click from off seems to go to some type of ramping. They don’t mention if it gets memorized or not. Do not assume smooth NarsilM type ramping, though.