Yes. The clones come from mature female stock. My method of identification relies upon letting them get old, after a period of time they will force pre-flowering. I usually keep my mother plants approximately 16-18" tall and assuming I run a bi-monthly clone/fill session (fill one channel every two weeks, get rotating harvest going) I can take way more clones than I need, usually betwen 30-40 from two mother plants.
I have grown larger plants, big enough to overtake the
grow lights and hit the ceiling. I can pack equivalent yields with a bunch of smaller plants and in much shorter time versus the larger plants. I have thought about taking the big NFT systems I work with and tuning one for cannabis, sell it to dispensaries or pharm companies, like the guys that make Sativex.
You don't want to cut off the leaves of cannabis during flowering, just about 1/3 of the way back from the tips. If you're looking to increase THC production, A.switch to the highest-power properly-tuned
led panel you can afford, B. add 290nm UVB, C. push the absolute edge of flowering times. Start with 12/12 lighting, push it to 13/11 or 14/10 if you can, this works usually around week 5-6 for indicas and 12-14 for sativas, although certain strains, particularly those from right at the equator, do not tolerate this at all.