Hey there, welcome to the forum! Design looks very tidy.

With N20s what is the best amperage for 4? A 2S lipo will be plenty voltage wise, but will a 300Mah pump out enough for 4, or do I need to go higher?
You'd probably be OK with 300mAh if it is just a pusher though it is always worth overestimating in my opinion if unsure.