You ever used eGo mini's? 350mAh or 450mAh
I think standard resistance on the cigalikes is 2.2Ω
510-X is a 400mAh battery and smaller than a eGo
https://www.fasttech.com/p/1401204
I have a pile of 350 ego's already.
I am not too worried about how many charging cycles I get, I consider batteries a disposable device, I am only concerned about thermal runaway. The 510-x has the weight too far out. I am going to take apart of few batteries and see what kind of thermal protection they have inside of them.
2 ohms will be safe in them, I am going to test all of the cartos I have and the ones below 2ohms I will use for other purposes. If I only get 30 recharges out of them (have gotten more than that already) I am fine with it. I am just going to avoid blow ups.