Andrew -
I've been collecting and growing, when I lived in Boulder Colorado USA for 40 years, all sorts of cacti, South African succulents, et al. I'm not the expert as some but I would say you are right. I'm not sure what luck you'll have trying to root a leaf. I had both, good and bad luck. As they say in the cacti and succulent world, "If you wonder whether you should water - don't." I have a succulent right now whose head, for some reason, rotted off but plantlets all along the stem are coming out now. I had a dark reddish aeonium too much in the shade and it got sick so I broke it off, let it dry, and covered up the stem with dirt and forgot about it. Now it has new plants coming up all along where the stem was buried as well the original larger head. Hope this helps.