Sorry if I wasn’t clear on the two switch method. Tail switch is an on/off function only, rapid strobe like taps, long press or full click it’s on/off only. The electronic side switch is mode selection only. So if I had it set on medium it’s medium every time the tail switch is manipulated. This is to keep the light from mode jumping when you need what you had set it on.
Just looked at the K2 and I like the overall style. I looks like it could be a good foundation design to work off of. Sounds like an internal shelf/pill setup will give us the most options to meet what we want. 22mm driver seems to also be what we are looking at, at least from what u have gathered.
This sounds nice! I would be in as long as there is a tail switch only.
DALE! You simply MUST get off that pain medicine! You probably think you see a lizard now!!! Lizard?? 
Freakin Sick!
You’re the Master, bar none!
TL. That is the worst picture of a blue whale I’ve ever seen.
If length is a concern then optics are generally shorter than reflectors.
P60 refectors in a custom light can have a screw in pill. 4th picture down from the top.
If you remove the tailcap switch the light will be shorter again. Saying that an electronic switch will need a special driver made to incorporate the switch to keep the length down and extra machining in the body or head to get the switch working on the outside world.
If TL makes a light I would very much like one though the good wife cannot ever find out.
Edit to add picture.
Here is a picture of three lights to give an idea on head diameters.
Left to right. Custom P60 as linked above, 29.8mm, standard Solarforce L2M, 32mm and a quad optic, 29mm. The two outside ones diameters are as small as practical that I would make the head diameters.
This link is an actual 26650 light using a P60 reflector with screw in pill. I dont have this light anymore so cant measure it. I think i gave it away here.
I hope this all helps.
If TL makes a light I would very much like one though the good wife cannot ever find out.
I reckon I could arrange that steve.
we could share the freight
Ok, understood. I don't care for this type of operation because I want everything available off the side switch - I don't want to change hand position, or use two hands to turn the light off, for example. With the "Werner style" mode selection, you don't ever have to click thru high modes or strobes to turn the light OFF, and I've made that even easier by being able to turn the light off in one click.
The basics of the mode based Narsil UI:
From OFF:
- click to moon mode
- hold to max/hi
From ON:
- while mode changing, click to next higher mode
- hold to next lower mode
- if in a mode for a while (least ~1 sec), you are locked in, so a click turns the light OFF
This is without mode memory. The goal of this UI is simple operation, know where you are starting from all the time, and never have to click thru higher modes.
For tactical tail switches in Narsil, I implemented something similar to what you described: complete e-switch support as described above, but full mode switching with memory from the tail switch. So you can choose a mode via the tail switch, then the light will come in on in that mode the next time powered up.
That sounds like a great UI Tom and I’m excited about Narsil.
I like the UI Tom is describing. It sounds great to me but then again I will be using the light more as a general purpose light and not in the same high stress situations that Texas Shooter will be. I understand TS desire for the simple ui of a tail on/off and side mode switch.
So I believe to able to get anywhere further on this we have to decide shelf or P60? What does each person want?
I have the LD-2 in this Extended Courui with XHP50. The tail cap functions 3 levels with memory L/M/Turbo and off (lock out). So what ever level you turn off at I will turn back on at, and the E-switch will pick up on that level and with a quick click move up and double click move down. With direct to Turbo from off (e-switch). I leave the tail cap in LOW with the FW switch I can get to the level I need to get to the E-switch while its ON. Or Medium, so when I turn it on, it’s in mid level and if I need Turbo just a quick click, to Turbo or double click the e-switch for Low. My 2 favorite set ups. 
The LD-2 is current regulated with a resistor you can set the current and also NTC Temp controlled. I really like this light with this set-up, not worried about parasitic drain with (6 ) 30Q’s 
Just thought I’d throw this out there too.
Yep Kawi, I thought about the LD-2 but it might have heat issues running 8A to a triple.
The KISS rule applies to a first responder type light. With these complex user interfaces like Narsil, while you yourself might understand how to operate it handing it off to a fellow officer makes for a non functional light. Straight forward basic simple operation is a must so it transfers across the board in emergency scenario’s…. a woman is hanging by her seat belt in a car that is dangling off a bridge, who’s got time to figure out what the switch does? Or where it is even?
This is why I prefer tail clicky only. The side switch can be difficult to locate in an emergency (or even non emergency) and with gloves it can be not only difficult to find but hard to operate too. (Think Firefighter, big heavy gloves, yeah, one switch, in the tail, hard to go wrong with that.)
Yea, I suggested the LD-2 as well in a pm just a few mins ago. Downside is no switch indicator LED support, no 1 or 2 cell option (not a buck driver), but can be configured for 8A max with a resistor change.
Edit: Ok - good luck with this.
The LD-2 in the Courui is set at 9amps 2S3P. I have some LD-2’s set at 12 amps for XHP70’s. I have a LD-2 M2 4S coming for a XHP35. It’s Linear, temp regulated and current controlled. Proper heat sinking and potted like all rough use lights should be, the driver is fine. As far as tail cap and E-switch it still works. Just like you said Tom no lighted indicator option. But maybe Niven could make what is needed? I don’t know just throwing it out there!! I too would agree Tail cap only, just like 90%of my Lights! :+1: Edit: But with the tail cap being able to set levels and e-switch, the tail cap could be used in an emergency and the e-switch for search and rescue???
I forgot about that, yeah, the LD-2 would be a good choice and has a nice option group from power levels to UI as well as duplicity in the dual switches.
Definitely something to consider, and a BLF member driver as well.
I have a few of these LD-2’s Dan, if you’d like to play with one to see exact size and functions…
If you all are talking about a flashlight the size of the LD-2, I’m out. I thought you were going for a “semi-pocketable” flashlight like the DQG but not quite that small. #MyTwoCents
Dude, we’re talking about LED4POWER’s LD-2 driver. 
17mm, check out Kawiboy’s links…
Edit:
The LD-2 with 6A set up would probably be ideal. They come with NTC resistors that attach onto the actual mcpcb near the emitter so thermal step down is accurate and precise. I’ve forgotten just how nice these drivers are, and I’ve got 7 of em sitting on my bench unused! lol
EditII: For accuracy, scratch the 7, I’ve got 6… modified one for 12V 4 Series XHP-35 in a big MaxToch light and just last week I put one in an Sinner 18650 Ti/Cu triple. I had 8 to begin with.
Bingo! Right on the mark. All of the lights I have built for first responders are exactly that… fast, simple to operate and typically 3 mode, LMH. They have never even wanted a side switch…always a tail switch and most of them have wanted that tailored in adjustment to their exact liking. Some want it so if they breathe on the switch boot the light comes on… others want it almost a full depress.
That being said, I figure for the most part not one of these lights will be the same as when shipped 2 days after arrival to a BLF member. 15 minutes for Dale! 25 minutes for MRsDNF! (Aussies are slow) …. SO…. in my tiny mind, we could do a set of internal component dimensions and owners can then do anything within that space that will fit. Narsil, Snorkel, Santa Maria, …… TL