If you watch the clicky UI video in the original post you can see a demo of how to do this from about 7:10 to 7:35
Yes, my operation is the same as video.
In the video you can see it output low red at the bottom of the brightness ramp after activating the option. Yours does the same?
Yes, repeat many times.
It may be a bad current conduction. When into the low brightness, and soon completely extinguished. After about 3 seconds it lights up again.
It sounds like your white and red regulators aren’t operating at very low levels. What type of Amc7135 did you use? Do you know what the logo on the parts looks like?
Like below, (sailboat?) but 7135 35K
It looks like you have the 380ma version of the 7135. They have been known to not light up at very low pwm values. If I remember right they can have troubles with pwm values as high as 10 where as the 350ma version is stable down to 3-4. I think anyway.
Edit:
Also, it’s hard to tell from the pics, but are the grounding tabs for each chip good and soldered?
Oh, that should be
I use the 380ma version on the R,G,B channel.
Others use 350ma version.
Unfortunately that brand of 7135s has issues lighting up at low levels. I have been having a hard time finding the good ones recently. There was some discussion of it in this thread: Shorten your 7135s for space-constrained mods!
I have just bought 300 from China, I can send 100 to you. or you want more?
I’ll send you a PM
The original circuit
SKILHUNT DS10
It’s a star? It’s a bulb? no, It’s a super flashlight.
TEST：Speak Chinese
https://youtu.be/AkWogEWyK0U
Looks awesome Steel! Thanks for posting your pictures
Steel: looks like you used an amber LED in the place of the UV? I’d be interested to hear why you chose that. It’s interesting! And did you have to modify the reflector in your host to make it fit?
Because UV LED is expensive. Only bought one.
Amber light looks very comfortable.
Yes, there is a little bit of modification and expansion
dual switch
Crop that photo and that's a sweet avatar! 
Looks great Steel! Dual switches makes the UI a lot better right?
So you have installed MELD-X in the Skilhunt DS10, the Fenix E35UE, and one other? What is the third light?
Wow, looks impressive!