On the batteries for the HF light, I asked this here a few years ago and the answer was vape shop or Li Ion Wholesale; and definitely not Amazon or Ebay. I bought mine from Li Ion. I think mine are 2300mah, and they are protected. This was a few years ago, but from what I read, the 3000+mah batteries weren't really recommended. That may have changed now.
I personally will not charge the batteries unattended as I don't trust them to not cause a fire. Yes, a one in a million, but still.... This was discussed here a few months ago and there were several people that said they almost had fires, and several said that it couldn't happen. A few weeks after that thread there was an article in a local paper where a guy sleeping was awakened during the night by his smoke alarm. He ran into the living room and saw that it was the Li Ion batteries on fire that he left in a charger. Thanks to the smoke alarm the damage was minimal. But if he wasn't home, or no smoke alarm....