If I told you I'd have to kill you! Well, I don't wanna say who it was because I'm not sure on the timeframe, and there have been delays before on this sort of stuff, but I would rate the source as "highly credible".
Could you share the data for all 4 samples instead of just the emitter averages? It would be interesting to see the spread within the emitters as a backdrop to the spread between them. Especially given all the variances just in the data sheets.
Sure - TangsFire has a U3. It's a Chinese U3 . The only real U3 in a light I'm aware of was the ArmyTek, but they ran out pretty quick. Since there was a real CREE batch of U3's released a while back, all the marketing hyped Chinese sources claimed they had them. I finally had enough of these false claims and proved it by comparing one source's claimed U3 to T6's and found the T6's equal or brighter, and U2's definitely brighter. If they claim U3, like TansgFire, chances it's a T6 at best.
- now this I'm feel'n!! "Trust in Hank" - the only trustyworthy source on that side of the planet. Illumn, IOS, MtnE, Cutter - only ones I know of to trust bins and tints from.
I bought 10 XML-2 U3 2C tints from Cutter a while ago. I went back 2 weeks later and bought the last of their stock which was about 4. As far as I know they have not had any since. I have in the one light, its a triple, two of the XML-2 U3 2C and one XML-2 U2 2C and I think I can tell the leds apart shining the light on a wall up close with brightness but probably kidding myself. Heres three of the most scientific pictures l've ever taken with the light rotated each picture.
If you could get specific tint info from Mouser, yes. I know in the past all they had was the range grouping. DigiKey of course, as well - not sure if they carry much though.
The problem with Mouser & Digikey is that they're expensive compared to the other options. Even buying 500 LEDs they are still a little bit more expensive than what I charge for the bare LEDs! The only way to come out ahead is to buy 1,000.