Your first grow is looking great Cehster, they look more on the Sativa side, you can tell from the thin shape of the leaves. You can expect them to continue to stretch as they flower. It looks like your in for a decent yield for your space to me, what light are you using?
The biggest fastest growing plants will almost always be males, they will also normally be the first to show sex. A slight burn to the tops at the early stage can be strangely beneficial a bit like topping a plant.
I'm not too sure about up potting as my 12/12 from seed grows were in Coco using 1l pots, you can get away with much smaller pot sizes with coco. I would say in your case it would make sense to up pot once they show sex to the biggest pot possible, it seems important to let the roots spread out in soil.
The biggest fastest growing plants will almost always be males, they will also normally be the first to show sex. A slight burn to the tops at the early stage can be strangely beneficial a bit like topping a plant.
I'm not too sure about up potting as my 12/12 from seed grows were in Coco using 1l pots, you can get away with much smaller pot sizes with coco. I would say in your case it would make sense to up pot once they show sex to the biggest pot possible, it seems important to let the roots spread out in soil.