Where to buy parts?

I'm not that familiar with where to buy parts for torches, so basically I want a LED with the most amount of lumen's that is 3cm in diameter or less, I can use either 1x 18650 or 2x 16340 and can you please show me a driver preferably 17mm or less(if there is non that size 3cm or under will do) that will deliver the maximum current the LED can handle. Many thanks and sorry if it sounds like I want to be spoon fed.

go to fasttech, buy a c8 host.
$10.82 Convoy C8 DIY LED Flashlight Host - emitter and driver sold separately at FastTech - Worldwide Free Shipping

and brightest led so far (1200lm at 3A)
$5.22 Cree XM-L2 T6-4D 1200LM 4300-4500K LED Emitter - 16*1.6mm aluminum base / 10W / 2.9-3.7V / 3A at FastTech - Worldwide Free Shipping

and driver
$3.31 8* AMC7135 4-Group 2~5 Modes LED Flashlight Driver Circuit (Nanjg 105c) - 3.0V ~ 4.5V / 2800mA constant current / 17mm at FastTech - Worldwide Free Shipping

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humm I just found this led I was thinking if I use 9x 16340 I could get 33v but how can I limit the current, I would need to limit the current to 3A, 3Ax33V=99Watts.
and if i make a custom host 5-6cm in diameter and 35-40cm in length it should all fit.

Home Electric DIY 100W LED light Lamp SMD Chip Cold White 9000-10000LM DC 30-34V | eBay