Sorry I cannot say for sure which dropins fit. There is a lot of information out there and it gets confusing on which fit perfectly or may need minor modification.
I would talk to one of the dealers for suggestions. A few come to mind - BOG, PTS, Lighthound, Batteryjunction to name a few in no particular order (I hope I did not leave any out). These are dealers on CPF and are all very reliable with good knowledge.
You will also need to know if you intend to use only 1 18650 battery or 2 CR123's for best results.
BTW - The Pila charger is a very well made charger and I think it is of higher quality than some of the generic ones out there. I believe it also has a little higher output capacity to charge the larger 18650 cells a bit faster.