Not sure which side you mean by bottom but I just made sure that the part of the leaf that
was attached to the stem is very near the soil. I think when that part senses the damp soil, it will send out roots. Right after I posted that photo for you, Gigi, I replanted those plantlets to another planter and the little buds all have roots with the original leaves still attached except for a couple where the mother leaf shriveled up. I will wait a little longer before putting into indiv. pots because space is getting to be an issue.
I will put your name on them in case you call/type for them because as you remember, I have that 3 tiered monstrosity that I have to water with all those echeverias in them. I actually added 2 more and removed a graptosedum and a graptoveria 'Debbie' to make room for the extra echeveria. I have an extra Grapto 'Debbie' baby if you want one...