I'm an FNG here so I'll throw etiquette to the wind I guess. I have had such great luck not waiting to callous the end that I don't even bother anymore. I cut from a large branch and stab it into a pot of fresh cactus soil and wait about 3 weeks and get leaves. Out of about 20 cuttings I've lost 2 and it was a center cut with no top, however I have done several center cuttings and got rooted and flourished.
