yes clippings need 24/0 light inorder to root properly, a common practice to determine the sex of plants is to take a few clippings from each plant in question, work your magic as if you were cloning the clippings, pop in your rockwool / Rapid rooters, and into cloner tray with dome (im sure you got something even a 2 liter pop bottle is good enough), just gotta keep the RH at proper levels for the clones stay healthy, and put them into 12/12, keep them in there and mist them once or twice a day for about 14 days, after 14 days they SHOULD be flowering already despite the fact that they didnt root at all, youll need to mix up a very mild "starter solution" to spray them with daily so they still get the food they need and continue growing. you can find some videos online about the whole procedure. its worked for me in the past, had a nice branch with dime sized buds and absoutly 0 roots extending into/out of the RR, pretty much only had a swelled stem in the RR that was white-ish, so the start of roots.
sorry for the runon again lol, hope this helps, if your confused look at some videos on youtube