Personally I would put those clones under 24/0 for one this helps kick them back to veg if they mom was in flower, also you want pure veg and want that clone to do everything it can to sprout roots. Also you need to keep that rock wool very moist for root generation. I use a small self made bubble cloner, that I made out of a small rubbermaid, itsl ike 4" tall and big enough for 6 2" neoprene inserts, and 1 large cheap air pump and 2 large air stones. I then take the clone, skin the last inch of the stem with a couple small vertical cuts with razor blade, dip in the cloning gel (I prefer gel) place those in the inserts with the stem sticking about 1-1.5 inches in the the tank but above the water line and let them go, once I see some good root growth I plant them in rockwool and go from there!
I made my own version of a bubble cloner for about $25, most expensive item was a the air pump.