More veg time and filling your SCROG net fully = more yield...... so a 4x4 would be the go.
5 gallon pots might just be enough, but if you have the space, 10 gallon pots would definitely provide better gowth and there would be less issues with the roots running out of room and the soil building up with nutrient salts long term.
However, if you really want to help your girls, go to 18/6 ASAP!
All plants, cannavis included, NEED sleep to finish their photosynthesis cycle and have a correctly functioning metabolism.
A plant with an incorrectly functioning metabolism will NEVER be as healthy as it can be.
Everything on planet Earth is designed to live with "circadian rhythms", a cycle of activity followed by a period of sleep.
The MYTH that it is OK to grow cannabis (including auto-flowers) for weeks/months without sleep needs to be removed from history!
At this age, you should be on 100% light intensity too.