Hey, I would def get some plastic, or something down, or your carpet will get ruined. Doesnt look like there is anything under your pots, and, spills happen. Even if they are showin sex, there is no way to tell in those pics. You would need really clear pics of the nodes. As far as the "stretch" being an indicator, you could have females stretched also, depends on distance to the lights, and lots of other things. Just be patient, and wait till you can see pistils or stamens. (hairs or balls) Most likely, all you will find first is males, as they seem to show about a week or 2, maybe more, sooner. I started with 26, and ended up with 9 males. But, I am outdoors, and lost some due to animals and weather. As far as the transplant, it looks like they are about ready. If you feel comfortable, slide one out of the pot and see what you see as far as roots. If they are wrappin around at the bottom pretty good, then its time. As far as pot size, it all depends on how big you are gonna grow em. They say a foot for every gallon pot size. I got some in 3.5 and 5 gallon buckets, and the bigger ones are about 4 ft tall. You will def want bigger pots before you go much farther. Before they start flowerin. They are lookin good, tho. Keep it up.