I am about to buy a Convoy S2 from Aliexpress. I will be using it only for spotting things for very short periods of time, so I’m thinking that the bin/tint U2-1A and 7135x8 color would be ideal for my use. Is this correct? Thanks for any replies.
Most people prefer neutral white (3B or 4C) over cool white. 7135x8 will give you the most output, power consumption, and heat of the different driver options. That’s fine when you’re using the light briefly.
That U2 1A in the S2+ is obnoxious, in my opinion of course. Get one and replace it with a XP-L V6 or a 5000K Nichia. Both pretty cheap options.
My favourite stock Convoy S2+ is the one with XML2 T6-4C, although the XML2 T6-3B is also nice!
If I would say, chose one of these 2 instead of U2-1A!! Possibly the T6-3B will be the best option!
About the number of chips, the 8*7135 will heat faster on the highest modes, but they will also give you the highest modes too! Careful when leaving the flashlight unattended, I guess is the major concern.
Buy from Convoy Store at AliExpress and chose the S2+ that suits you (with Biscotti firmware, not a 3/5 mode driver)! Also, if you want a more throwy flashlight, get one with XPL-HI (U6-3A would be my recommendation as well) so that can have a little more intense hotspot!
After getting the 4C (trust me on this) get a coupla 20mm TIR lenses. TIRs mix much better the light coming straight out vs from the sides of the chip, so you won’t get a fried-egg beam, but a beautiful beam the color of warm sunlight.
You can do that with the TIRs at your leisure, but do get the 4C. You won’t be sorry.
If this can help, I will show you 3 lights!
Left - Convoy S2+ (XML2 U2-1A + Orange Peel reflector) - cool white
Middle - Modded light (XML2 T6-4C + Pebbled TIR optic - 60º ) - neutral white
Right - Convoy S2+ (XML2 T6-4C + Orange Peel reflector + a piece of diffuser sheet from member Boaz, but not DC-Fix) - warm white
Here you can see the tints and a little bit the beam pattern. The TIR optics give you a more homogeneous beam, while the reflector have more shifts and a stronger hotspot.
Also, if you prefer a light that doesn’t hurt your eyes so much, go for the 3B or 4C ( this one specially if it is for indoor environment). Then put a TIR like Lightbringer said or use some piece of diffuser over the lens to make the beam better! 
I’ve bought 6 Convoy lights: S2, S2+ (2,) M1, M2, C8 and was gifted a custom S2+.
My S2 I got a few years back with an older XM-L 5T 5C LED and it’s pretty warm. Probably my warmest tint, but not a golden/yellow, tint. My latest was a violet/purple XM-L2 U2 1A for my GF and it’s pretty much a clean white with no purple/blue.
I’ve got tints in between for the others.
They’re cheap enough where you can buy a couple/few and fiddle with them.
Except for one S2+ from no defunct James at UK 3Tronics, all of mine are 8*7135 driver boards. I’d rather have it and not need it than to need it and not have it, but they do heat up on a freshly charged high drain 18650.
Chris
If you buy on AliExpress, make a note that you want the biscotti firmware…. Might be confusing at the moment but you’ll be glad you did… You can have a light with 12 mode groups … Instead of 2 mode groups….
Thanks for all the helpful responses. This forum is awesome. Originally, I was thinking of buying the S2 because it has more throw than the S2, and I want a lot of throw. But everyone is recommending the S2. so I’ll get that. I think I’ll get a T6-4C, XM-L2, 7135x8 and a XPL-HI, U6-3A, 7135x8 both with Biscotti firmware. I would also like a forward clicky in each. Is that possible? Are the 20mm TIR lenses available from Aliexpress?
This is where I bought mine, Simon Mao… he can answer all your questions…
I have all mine with reflectors, smooth or orange peel… Never thought about TIR…
Hmm
Biscotti firmware info
Yeh, you can get ’em from AX, Amazon, LEDSupply, buncha places.
Perfect combination 
BTW, if you want more throw, on the one with XPL-HI ask Simon (on the “message seller” part) to put a smooth reflector on it
The T6-4C, ask for a Orange Peel reflector
Nice way to go!!
EDIT: About the forward switch, yeah, you can ask for them as well! But please not that the reverse switches are better to make the Biscotti configuration in the group mode you want!! So, you may ask for Simon to include a reverse switch as well (and adjust the price) or buy them on the store!