Thanks for the updates and all the effort you are putting into this!
It will be worth the wait for the right tint bins.
Thanks Blue, payment sent…. 
I’ve sent everybody on the list a PM in less than 2 days this time.
Now, we just have to wait until I can make the final order for the springs February 19th, since they take more time to make+ship than 2 day shipping LEDs.
PP sent
PP sent!
Excellent. Here are the final specifications:
Large spring:
Spring upper diameter: 6,00mm
Spring base diameter: 9mm
Spring thickness: 1,0mm
Spring height: 12,00mm
Total number of coils: 4
Plating: Silver electroplating
Small spring:
Spring upper diameter: 4,00mm
Spring base diameter: 5,5mm
Spring thickness: 0,8mm
Spring height: 10,50mm
Total number of coils: 5
Plating: Silver electroplating
The springs have been ordered.
Will post updates as they come.
Wow I didn’t know the springs knew how to post on a forum! 
Yeah you’re right.
The springs have become so advanced that they’ve become sentient 
But seriously, with a silver plating and removing a coil from the large spring(which will increase the plastic deformation from 0,9mm to 1,3mm instead), we may be able to get even higher current from the dual spring array.
I’m hoping it makes a noticeable improvement in my BLF Q8 performance. I’ve made no other mods, but I’m using nice cells. I’m thinking about changing emitters to HI for a little bit more throw like the Sofirn Q8 but not sure of that yet.
I received my “early” 3500K SST20 leds finally. The mail went wrong and they came back to Blue and he re-sent them.
I reflowed one on a 16mm DTP board and frankly, I’m not impressed. I measured tints at 350mA but other currents do not significantly improve things. The CRI is perfectly fine (over 95CRI in all measurements) but the tints are not below the BBL but in most builds will be clearly above it.
Bare led measured straight from above is ok:
Same led measured at 60 degrees to the side:
Same led with small OP reflector on top (from an S9), the hotspot was measured:
So there is nothing rosy to measure, also when inspecting the beam from the S9 reflector by eye, I see the all too common tint that hints towards yellow/green instead to rosy. And as usual it is a fine tint by itself but when compared next to a 3500K 92CRI Nichia 219C beam it loses out bigtime.
This matches my observations of the 3000K from Hank. Either there are huge variations in the emitters or the manufacturer’s binning is wrong. Minus green filters make the tint much more acceptable (to me) and is the only thing keeping me from swapping them out for XPL-HIs or 219Cs. It’s a shame the tints tend towards yellow/green because I think they’re in a sweet spot of being relatively low price with high CRI and good throw.
I have a hunch that if you want less greener tint, choose the lower flux bin, since green is the one thing that will surely add to the lumens. I remember the high CRI 219C D240 bin being greener than the lower bins at least.
Yeah it’s a problem I’ve encountered too. Tint variation, even for a GA3 tint supposed below BBL, is quite large.
There are samples of the SST-20 3500k that are just on the BBL at 1 amp, while others are better in this regard.
This what halted me in my search for 4000k SST-20s and LH351Ds:
I need to order pick 5000pcs to customize tint bins, but without the ability to customize flux bins.
The 3500k from Mouser was a stroke of luck on my part, along with the 3000k sample.
djozz… what hardware did you use to get that tint reading in your test? It looks interesting.
A Gossen Mavospec Base, which is a handheld spectrometer targeted to the professional lighting market (but is bought every now and then by a hobby freak). There is similar devices around by Sekonic and other brands.
Cool… yeah I was hoping it was something much less expensive.
I've read elsewhere that brass screws can be purchased for the Q8, and will also help get you a bit more brightness. I would definitely recommend XPL-HI or XP-L2 over the stock XP-L.
Oh man the DUV is very disappointing. I was hoping it will be -.008 DUV with bare LED so even with optics, it would still not be green.
BTW, I’ve been considering buy a spectrometer for a long while but haven’t yet because of the price. Maybe in the future I will. Why did you choose the Gossen Mavospec Base over Sekonic or any other brands? How does yours compare with Maukka’s spectrometer?
I’m not sure how maukka’s measuring setup is done, it is not a handheld spectrometer like mine but works via a computer, and possibly an optical fiber is used to collect the light.
And I did not do an extensive search for the best, cheapest or most versatile spectrometer (the Sekonic C700 is cheaper and more versatile, not sure about quality and accuracy, should be ok too), the Gossen spectrometer was recommended and sold to me by a dutch lighting company that also very friendly helped me with calibrating my luxmeter last year. Call me lured into this one 