bubble cloners are super hard to get the water level right: too high and stem rot, too low and clone never roots. I would recommend rooting gel and RW. No joke, I was able to root some 10 inch flowering clones in the tiniest of RW cubes without any problems (not recommended, but demonstrates success rate of RW).
It will depend a lot on the plant you cut it off, but most clones need a TON of humidity. Think of creating a humidity dome of some sort. And be careful weaning them from it. I've had more clones die after rooting this way than fail to root.