BOY! A concept right out of the 70's. Guess history does repeat itself.
It's better if only one person does the entire room, to avoid obvious variations in application.
Crumple the rag, dip in a pan of paint, easiest way to coat the rag. Practice on scrap cardboard til you get the pattern you like.
Patty: Olivia is right... and I've found that you should do the room in ONE day... as that will help mitigate variations.