I recently plastered a tower that I couldn't get drywall to, due to the circular staircase that led to it. It was my first true plastering job and even though I probably wasted as much material as I applied, it came out pretty nice. I'm doing the walls and ceiling that lead to the tower now and its kicking my butt. Not only do the walls circle around the stair but they also arch into the ceiling. Then the ceiling turns convex from the concave arch of the wall. It's like plastering the inside of a bowl and then plastering the outside. Any tips?