I’m going to try to learn Eagle real quick 
to make some alterations to the board that will make it a bit more versatile. (I don’t want to keep pestering Helios, and I’ve wanted to learn Eagle for awhile anyways)
The lit tailcaps look great and you're still in the early stages. Way to go bro.
Best wishes on using Eagle. I just learned to use it enough to design a board recently and it was a challenge for me. Just a lot of info you need to know that isn't in the tutorials and such. Worth learning though IMO.
This is what I am planning to do in Eagle. Before I go through that work, can anyone see any basic flaws in my design?
The resistor and diode are in series, the led’s are in parallel. Alternatively, you could put the first led on the D1 pads so that the LED’s are in series.
Seems plausible. Is the micro switch you searched in the other thread also intended for the lighted tailcap?
I was thinking about it, but I don’t think I found one small enough.
Well, other than getting it to upload to Oshpark correctly, it’s done.
Ok, Oshpark issues are sorted out. 20mm Dual-LED board is in the OP, ready to be ordered.
Great work Pilotdog! How bright do you think a pair of blue 0603’s would be? I’m looking for about twice as bright as a tritium vial.
it depends on the resistor value but with almost any value it will be way brighter.
Ordered all the parts just got to wait for them to turn up and give it a go 
I don’t have any trits, but if use anything lower than 4.7k in the tail, its basically like an always-on moon mode. It’s enough light to walk by in total darkness.
In total darkness if I hold my watch up to a page of a book, I can just barely read it. I definitely can’t navigate by it.
I see at the store you linked to the highest that they have is 2.4k ohm resistors in the 0805 size. I must be missing something.
If you use SMD Led’s you’ll want to pick up some 5/16” white nylon washers as well.
The blue one is with 2 dip led’s sitting above the retaining ring. It has a 5.6kohm in the tail. It is far too bright to keep by your bed, but is a good brightness for showing off to friends in daylight.
The red one has a single 0603 led under a nylon washer (0805 fits just fine, but I didn’t have any at the time). It also has a 5.6kohm resistor. I’m not sure if it is because the red led isn’t as bright, or the nylon washer blocks a bunch of light (or both), but it is the perfect brightness for a bedside light. In broad daylight the red isn’t visible, in a lit room it is barely visible, but in pitch back with your eyes adjusted it is a nice even glow that doesn’t make you squint if you just woke up.
edit: sorry, i bought my LED’s from lighthouse but I already had the resistors. Fasttech sells multipacks for super cheap
Perfect, that’s what I needed.
Try this:
GITD Tailcap + UV LED
The Tailcap will be enlightened from the inside…
If I understand this correct: All I need is one of the boards, the switch, a resistor and a LED - nothing special like a cable running from one end of the light to the other or a special driver or something like that?
You don’t need to run a cable or a special driver. You will need to add a resistor to whatever driver you are using though. I have it working with 3 different driver designs, but I suppose there is still the potential that a driver may not function with this mod installed.
Can you link where this action is described for dummies? 
Edit:
So, just adding a resistor between plus and minus of the driver/battery - correct?
So minus becomes plus for the LED through the resistor and the electrons can float…
Just ordered a few of the 17 and 20mm ones… can’t believe how cheap OSHpark is…
My first order from them btw
Correct. I just solder a dip resistor between the batt+ driver spring and the driver GND ring. I’ll post a pic of one of mine later. Its super easy.
pilotdog 68 very interesting stuff you have done here. I’m curious if you have any info on how much battery life do these leds in the tail consume?
Yep. It’s in the top of the OP. It’s around 0.2ma.