Amp Draw

Yes, going with a larger spur or smaller pinion will reduce the amp draw.

In my experience the truerc 4s2P pack is a good solid 15C pack.

I'd quit worrying about amp draw and just watch the temps. If the battery isn't getting too hot, I wouldn't worry about it.

I'm running a 5S2P truerc pack in one of my trucks with a 1515 1700kv neu and the battery never even heats up.