Wow JoJoe those look great!! Personally since I don't have tons of room I plant mine pretty close in the pots, and since they're so little still its the perfect time!
How I plant these guys is using a pencil and make a hole in the soil then gently push the roots in and cover lightly. Also for the first week or so I only spray mist, I don't water. Just misting lightly every morning, and not the leaf just the soil around the leaf.
Expect that as the new plant begins to grow the leaf will die off, so don't be concerned if that happens.
I use cactus mix or make your own using potting soil, pumice or perlite and a little sand. I usually do this recipe
1 part sand
2 parts soil
2 parts pumice
Hope this helps
You're doing great! the plants look really cool
