Wow sweet. What tint are you getting? Might make a nice 2000K house light
Basically the same tint options as D4V2/KR4
Are the tubes interchangeable with the D4v2?
Yes, they are interchangeable.
Thank you so much for doing this, it makes me really happy. 
HANK, can Sst20 4k and osram (W1 or W2) be mixed in the DT8?
This isn’t a two channel driver, so no mixing different model LEDs. You could tint mix with the SST-20 family if you wanted I am sure.
HANK mixed sst and osram on a D18 so I thought he would be able to do it with this
$50.00 Hank lights are good fun,
$100.00 XP-L Hank lights are Zebralight territory.
Fun for me stops with Hank.
It’s technically possible but you won’t be able to selectively switch between them per se, above a certain power level all LEDs would light up, and it would look weird I would think. But having two channels on this light would have been pretty cool! Especially if you could drive both channels at once and independently.
Will there also be a Ti / Cu option, like the D4V2 / KR4?
Oh please, I hope there is ! Although the balance may be really off with the large copper head and small titanium tube
Needs a 21700 version of this light, more juice for the 8 emitters.
I’m trying to understand why the LEDs are in a 4x2 arrangement. Instead of a more conventional 2-3-2 (yes, I know, one fewer LED).
Is it just to be kooky or is there some practical advantage?
We wish the light as small as possible, as pocketable as possible, while 21700 will make the light significantly bigger,
which is not our intention.
How about 2x18650 in side-by-side configuration?
Could be done by having a single head that has sockets for two standard D4 tubes.
The thought of that makes me smile. It would be ridiculous but cool. I imagine using it would look like water dousing.
Ordered Black XPL hi raised switch ring amber backlight with magnet.
Technically ok, but when to use 2*18650, it will be hard to change the batteries, since you can not remove the screws every time to
change the batteries. Or to use the built-in charger, the light will become more bulky.
Hank can you mix mix sst and osram?