Lights for Xmas in route, need battery help.

Guys I have questions.

I bought the acebeam ec60vn for duck hunting and its my first good flashlight. (this is all new for me)

On Vihns website when purchasing that light he had battery suggestions so I purchased his suggestions, which, was an green efest 26650 4200mAh. With research, I bough an additional battery that's a IJOY 42000mAh.

I bought 3 Manker U21, what 26650 battery is suggested?

I bought 2 Arymtek wizard pro headlamps, and one 18650 keenpower 3500mAh battery. I need a few extras cells what should I get?

I bought the Acebeam K70vn, I believe it takes four 18650 protected batteries (according to Vinhs site) What do I need?


Charger question: I purchased the xtar dragon. What the heck is the discharge/charge/record function and when/why do I use it?

These cells are so confusing i.e a higher mAh (5000,5200) doesn't necessarily better performance?

One last question two of the Manker U21 will be xmas gift for two friends that know nothing about lithium Ion cells. What warning and hazards should I stress to them.


Thanks,
Happy Holidays
James