Good idea TrueBlue, but something not easily carried out methinks. First of all, the tester would need to find a relatively flat and long piece of ground, we'd have to worry about people walking pass "nice light! *Yonk*" And the further the light throws, the more we'll have to walk, thereby making the discharged time to measure time not constant across the board. Also with the lux meter, you're going to have to hold it pretty steady and at a straight on angle to the light, which may be hard without something to mount it and light etc.
I guess there's no real easy way to convey the throw of a light...
For example (real),
i've got two ROPs. A 2D modamag holder with 6 cbp's, metal reflector, UCL and a solderwicked spring. Hot cells i can get 40,000+Lux easy.
A 3D bored host, with 4x18650s, a low loss reflector, solderwicked spring, UCL. This light can only measure about 28,000 Lux or so. (The low loss reflector along with the cam mechanism doesn't allow perfect focus, but rather, a big circle of light followed by sidespill)
In real world usage, my 3D throws further than my 2D...yet my 2D measures higher. I think what's happening is the 2D has a powerful "line" of intense light then the rest of the hotspot weakens off. This "line/beam" of light at 200 metres away, can't really be detected with human eyes easily (or with my eyes at least). Bear in mind, the light has landed on brown coloured bricks, so it's very hard to detect, or whatever else your shining on (probably won't be white coloured).
Now my 3D shining at the same target, lights the whole target (actually a unit in my case) up, due to the lightspread of the hotspot being much better and also the hotspot being much larger.
So my 3D ROP in actual use, throws further than my 2D ROP, which has a 12,000+ lux advantage =/