if i were rockwool cloning then i would get 1-2 inch cubes depending on clone size. Then, soak them in water ph'd to 5.8 and sterilized with 1ml/l 30% h202. Then use a salad spinner to get cubes moist but no soaking; squeezing them ruins all the little air pockets in the rockwool. Then get ur clone, add a rooting agent if you have it, otherwise stick it into the cube. If the premade hole looks too big to hug the stem then turn it upside down, make a new hole with something and stick the clone in that. You want a snug fit on at least half an inch to an inch of stem in the cube. Then take your cubes and put them in some sort of propagator with a humidity dome. I use the jiffy pellet one, its just a thin plastic thing with a clear lid. The clones need the humidity. Put all your clones in cubes in this and mist once-thrice a day to keep them moist, but not wet. Some people put them into 12/24 hours of darkness on the first day with excellent effect, but after that 24/7 with fluoresents as close aas you can get them to the plants is fine. Once roots begin to show, then put them into your aero setup in a netpot with hydroton at the bottom to prevent the cube from being watered. The cube should be moistened by the hydroton wicking water up, but shouldn't directly be misted to avoid oversaturation. I use a 30on/1hr off during veg and it works well for my roots. They don't die and they don't get air pruned. If any roots are turning brown and shriveled increase your watering to 30 on/off. I do this once my rootmass hits the res water because i find the mass is large enough to dry too much in an hour. If you have the $ to get a 1 min on 5 mins off timer, get it and use it for all stages of growth; the stinkbud system is well proven and endorsed, even if i personally have found success with different methods.
watever method works for you you can use
this is hardly set in stone, but it is the collection of most of the tricks i have found online. good luck with clones
I have found that my clones take almost 30 days in bubbler dwc, and only about 17-20 days in a bubbler aero system. In soil they take 6-9. As long as they are green and the stems aren't covered in slime or black/green algea then your clones will root. After 30 days you might want to look at some new ones.