Convoy has released a 17mm, 3V, 8A buck driver with 5A and 3A coming soon
https://www.aliexpress.us/item/3256805582954343.html
I'm assuming this will fit the C8 and many S-series lights. 8A is suitable for the SST-40 and SFT40, but will likely be limited by forward voltage with most emitters.
5A is running a 519A, SST-20, etc... fairly hard, while 3A is a pretty average single-emitter light.
I wish they had these available couple of years ago; I moved all my self-assembled lights to 21700 Hosts because cheap buck and boost drivers were only available in 20mm and 22mm sizes.
I haven't been building a lot of DIY stuff lately, but I have a C8 I think is going to need one of these and the upcoming high-CRI SFT40.
According to the Convoy BLF thread there is also an 8A buck driver coming in 20mm size. That (or these new 17mm drivers with an adapter) enables more options for the S21A as well.
I ordered ten 5A drivers. I'm pretty excited about these. Anyone else bulk ordering and moving a lot of hosts over? Gonna build my first W1 S2+ too!
Ordered the S6 with CSLNM1 and requested the 5a buck driver for an 18350 pocket thrower, hopefully.
5A is running a 519A, SST-20, etc… fairly hard,
I think that statement might apply to this Osram emitter as well.