Lumens measuring contraption... (or just a pipe dream?)

I spent this morning dialing in a conversion factor. The first problem I had was that most of my lights are modified...

I managed to find several stock lights, & corresponding numbers from experienced members/reviewers here on BLF. It's not a large data set by any means, but it seems to scale well from small to large lights.

Below are the lights I used, & lumens from my pipe-meter after conversion factor, followed by other member's data;

DQG Tiny AAA version 3; 56 lumens (~60 lumens, _the_'s review )

DQG Bullet ; 208 lumens (220 peak, JohnnyMac's review)

K50v2; 1616 lumens (1638 - 1656, K50v2 mod thread)

EE X6 SE; 912 lumens (900+, JohnnyMac's review)

Convoy S2+ triple Nichia 219b DD; 1280 lumens (1279, MTN discussion thread)

------

Going from that, I appear to be "in the ballpark".