I have a large tray ceiling in my bedroom. The room is approx. 15 x 13. I am planning to paint and am not sure what to do with the angled wall and the flat ceiling. Should I keep the angled part of the wall the same as the wall color, then paint the flat ceiling white? Paint both parts one shade darker? Maybe paint it all the same color- walls, angles, ceiling. I wish I was related to a professional decorator!