PC Questions about Artificial Biomes

[Boltlord]

I am going to destroy all of my Crimson and Hallow, but I still need the souls and some stuff so I am going to make Artificial Biomes

will a 2 grey brick barrier around them be enough?
Monsters do not spawn in player placed walls, but if I place stone walls in that area and clentaminate it, then will that get monsters spawning on the crimstone walls?
Is it okay to make them outta stone and then clentaminate them?

 

[ruddthree]

1. You need at least 3 blocks of space/blocks in between biomes to make sure they don't spread.
2. The underground has little background walls. you're better off have none.
3. I'm not sure you can clentaminate stone walls. Even if it is, they would still count as player-placed walls and thus will not allow mobs to spawn.

 

[Boltlord]

okay thanks