Having had some experience of cuttings of Aptenia the last few months (call me an expert - not!)...
I find that stripping-off the lower leaves does not help, whether allowed to callous-over or not before planting. Such cuttings wilt and sulk; many of them shrivel and die.
By contrast, cuttings taken and planted straight away with all leaves still attached, fare much better. They may wilt somewhat for a while, but then they usually perk up and get going. I plant them only shallowly - I make a scrape, lay the cutting in it then cover with soil, maybe with a stone on the stem to anchor it and provide a little moisture retention.
Also, they root well in tap water. I found that any immersed leaves tend to rot (starting with going slimy), so I remove them. You can see from the photos that the roots are formed mainly at the end of the stem, irrespective of whether that corresponds with a node. Photos taken 17 days after going into the water. I can't say how well such cuttings grow when planted in soil, because I am only just about to do that...