Chad, Mark et al - my best result for leaf propagation is taking a leaf from near the outside of the rosette, trying to get a bit of the stem cells, propping up the leaf in the soil/chicken grit. Keeping this in shade, spray misting at least once per day, and after a week or so there are roots, this can then be planted, but still in shade, and watering a little more than other semps. I've had good success with any of the semps that are already fast growing.
But this water thing is interesting Chad, thanks for posting