Regarding the batteries, I think you should charge them as often as possible to extend their lifetime. Just like cell phone batteries and everything else these days. (The myths about memory effects came from a 10 yo technology and doesn't apply to lithium)
Regarding the leaks, I think it's normal. FWIW, in a primed atty, I use two drops from my regular droppers or three drops from my tiny bottles. More than that results in leaking.
I'm not having any issues with the batteries...They work perfect for me...I can go all day on a single charge...Why would I want to charge them before they are drained??