Awesome!
Excellent work, thanks for sharing 
You give a great leap if you upgrade to XML2 an dedomed, their values will rise up to the clouds 
Consultation, why there are so many wires to the leds? :~
Thanks!
Although I agree that there was likely good metal to metal contact (as I implied in my first post), I don't think the small amount of thermal paste was intentional. The pressure from the screws would have squeezed out excess paste and a thin residual layer (in the spots with voids) across the back of the emitter board would have been ideal. Especially given the semi-rough surface evident in the picture.
Seems like a mute point given that RaceR86's measurements show it has adequate thermal path for the stock current levels. It, however, shows that even high-end lights like this are prone to assembly line issues. All the more reason to go through budget lights before using on high.
I dont think you get get too much thermal compound under the mcpcb on this light though. Once its properly tightened down with the four screws any excessive amount of thermal compound will just be squeezed out. (like Ima4Wheelr said)
Either way, based on testing there was no indication that it was too little based on real life output and sag. (It was just a bit disappointing from a visual point of view since there could have been 3 times more without being too much.)
When all that is said. IMO the focus on mirror finish lapped mcpcbs, the need for thick heavy pills etc etc are in most cases highly overrated if the head is well designed. Even IF people would get up towards 1-2 degree lower emitter temperature, that would still be less than 0,5% gain at best...
Stock resistors on each separate channel were: R100 and R050. I ended up adding one R100 on top of those (on both channels).
Like this picture shows, (only that the R120 was changed with one R100)
There are two channels output channels, A and B (not sure if that is the correct term). Emitters are wired 2s2p. So its 4 wires instead of two. Its just the way they built it, because reasons. :D
Thanks for the comment. :)
With “thick” (high viscosity) thermal paste, I think the problem is that the MCPCB may actually flex, maintaining a gap filled with thermal paste! That said, you are exactly right - clearly Fenix had all that figured out and provided adequate everything.
This looks awesome, the main reason I didn’t want to get the RC40 was because of the battery pack. But seeing the light now is so tempting. Maybe I will wait for a update.
I can’t wait for the beam shot showing the before and after.
I think 2 dedome + 2 dome XM-L2 will be fantastic. If you can focus it well. Awesome throw and still have usable flood.
In this type flashlight, when dedomed, the flood not lose some much but Increases significantly in throw…This is seen in the tk75 
If you are not in need of such a large light (with built in charging and battery monitoring), go for the TK75. Even a stock TK75 (XM-L2 U2) is barely behind in the Lumen and throw department. Much better value if you already have charger and batteries, and much better as an allround high output light due to size.
I was thinking that the RC40 had a more compact handle (due to battery carrier and only 3 cells side by side), but its only 2mm slimmer compared to TK75 (which have 4 batteries side by side in a carrier). The RC40 is not in any way built as a compact light.
Ehm, dont have beamshots of the stock RC40.. Got a bit carried away modding it after I received it.. 0:)
I agree gaston01.