These are usually the size that gently lift them out of the soil and transplant them in a slightly larger container. However, you planted them in those little cylinders. Perhaps you could just transplant the entire ball (plantlet and all) into a slightly larger pot. I see that some containers have two plantlets in them. I would lift one of them very gently and place it into another container on its own. I suspect that the plantlet will develop better if it does not have to compete with a twin. If you cannot get it out in tact, I would just nip it off and thus loose one of the two. I would not cover them again at this stage. Good luck miss, keep us posted.