I hesitate...because I have one,but haven't yet tried cuttings.I do know-they like humidity but dont need soaking wet soil..doesn't have to be fern like watered as you might think a cloudforest plant would prefer.
In Mexico they actually grow ruddeal-like roadside weeds sprouting in fresh dug up soil. Sort of what Mallow weeds do here.
Again,best guess is a cactus mix for starters-fast drainage.
Where I got mine,-UC Berkeley botanical garden- all where said(labeled) to be seed grown. I thought that was an interesting distinction they would make a point of pointing out.
Last?, mine and the others hated being in a pot..quickly turning yellow,showing signs of stunting. It wasn't two weeks in ground when it regained color,vigor. So, my advice is when you root yours-plant out asap.

thanks stanofh... perhaps I will try UCb if I can't get this one to grow!