I didn't go crazy on details because I knew I was going to cover most of it up with paint.
I used this dark grey mixed with water and plaster of Paris first. As it was wet, it was perfect. The perfect color and consistency. But when it dried, it came out way too light. So I added the black and waited a bit to let it thicken up before I applied it.
I'm pretty happy with the results. I'm not quite finished yet, there are a few areas I want to touch up again and I may need to apply a top coat to seal it in when I'm ready. Also I made a few streaks I need to try to get out, Windex maybe?
I might do some browns and tans to give it a more earth look and less grey. Haven't quite decided yet.