OK, are you going to be able to water them 4 times per day?
Generally you would need an auto-drip system to accomplish that. If you are planning to hand-water you will be limited by lights and darkness.
If you can auto-water 4x per day I recommend 3-gallon.
If you can reliably hand-water 2x per day I rec 5-gallon
If less than that Larger
As I explain in my guide, smaller pots with higher frequency fertigation is best.