The trick for cloning or rooting avocados is the darkening process to to turn the stem white from lack of chlorophyll and then you add hormones and air layer. That is very hard for me, you need a dark room with a particular temperature, humidity and proper ventilation. I never had luck with rooting cuttings. A fiend even tried one of the hydro cloners with total failure.
The only thing left is to air layer in the summer heat with multiple application of hormones, like once a week with a syringe.
I got the clones from a friend and collaborator. It was a rare event but needed to see how the clonal would do in our soil. I really like them, better than Toro Cayon.