I do large batch Pheno testing And have a little trick about finding males. I have an independent to buy to 10tAnd have a little trick about finding males. I have an independent 2x2 tent set up for it on 12/12. I will take a cutting off of each plant and put it in a solo cup with some light nute solution. I can fit a lot in there at once. After about a week, they start transitioning and walla i know definitively what sex they are. If I was only doing a few plants here and there I wouldn't do that but since I do a lot at once, I need to know quickly