Hi, I'm trying to propagate succulents for the first time, I'm not sure what types a couple of them are but I do have a couple of echeverias and I think a Kalanchoe. I've laid out the healthy leaves I want to propagate and have set aside the main plant so the stem can callous over before re-planting. I have the leaves sitting on a piece of cardboard on my bookshelf, so my cats can't get to them. Is this okay, or do they need more sunlight? Also, do they need to be resting on soil rather than the cardboard? Thank you so much.