But to answer you question, more mAh - milliAmp hours - equates to more battery life; more vape time. But you do want to make sure your batteries provide at least 10 amps safely, this will allow your coils to go down to about 0.6 amps, which is pretty low. You want high-drain IMR batteries, for sure.
ETA: higher mAh is more runtime, and you'll probably end up around 2000-3000 mAh, that can vary pretty widely.