This is all very interesting. Here are some more details
The light:
https://www.imrbatteries.com/xtar-h3w-warboy-headlamp-flashlight-cree-xm-l2-u2-led-950-lumens/
When using a protected NCR18650B on max brightness the head of the light became uncomfortably hot. Protection I guess would be another variable however. When I Switched to an unprotected NCR18650GA, the head of the lamp is significantly cooler. It's literally the difference between me feeling comfortable using the light at that brightness or not. I'll get an IR thermometer and get some numbers.
My curiosity resulted in me using an even higher current rated battery, a Samsung 30q. When I used that however, the light began flickering and smoking. It smelled like a hair dryer. I quickly turned it off and both the battery and light are still working, which is nice =p. This makes me think it's an unregulated light however, and the 30Q put too much current in the driver. The 30q works fine in one of my zebras though, since I guess it's regulated. What's interesting is that the 18650GA improved performance, but the 30Q nearly fried it. This experience almost makes me feel like unregulated lights are dangerous.