Pay attention to the XHP70 thread.

Extreme High Power LEDs [image] [image] XHP50 LED XHP70 LED Size (mm x mm) 5 x 5 7 x 7 Maximum light output Up to 2546 lm @ 19 W Up to 4022 lm @ 32 W 4 die leds, but 4022 lumens? Imagine if it's pushed to higher amperage. http://www.cree.com/XHP?elq=5556dd484026485692f795293609a700&elqCampaignId=96 Links: XM-L2 Easy White MC-E MK-R MK-R2 MT-G MT-G2 XHP50 XHP70
As I said though in edit which by your quote appears you didnt see, personally Id opt for 18650 as they would make for a better fit in a tube, with less wasted space.