I'd say my 2000mAh AW IMR 18650s take roughly 5 hours on my 500 mA Trustfire charger. I've never timed it, but I've had it done in about 5 hours at least, so my guess is it takes a little less than that, which means it's not too far off the 2000mAh/500mA=4h formula, taking into consideration some inherent uncertainty.
I have several batteries exactly for the reason of having to wait. There's always a freshly charged battery at hand!

When buying a PV that takes 18650s, getting two 18650s, or perhaps a 18650/18350 combo in the case of the Vamo, is a choice you will never regret.