I had one of them NCR18650B batteries. While I sympathize that they do "last a long time" I respect the advice I got from here (mainly from Baditude) that because it's not a high drain battery, I am not using the best battery - so gave it away.
Just because it's not high drain does not mean it will not "work" - mine worked, but did I trust it after being told it's not ideal? Hell no. I like my front teeth! I jest, but really - it's not worth the risk.
Baditude's battery guides are spot on for people that don't "get" the differences (like me) I would recommend following the advice. It's just too risky to ignore it, honestly. Not meaning to be negative, but your health is important and a battery can do some serious damage if it is not up to the job it is being asked to do.
Just my mutterings - YMMV.