We repaired a part of our textured ceiling with a piece of drywall ( 2.5' x 4'). It's mudded and sanded and ready to be covered with topping compound. A friend of ours said that the topping compound needs to be thinned before application. He said a good trick was to add paint to thin it. It'll also dry whiter. Since I don't want just that corner of the room to have a bright white ceiling, I'll be crow's footing the entire room. My question is this: do I have to sand down the textured ceiling before re crow's footing it? What's a good consistency for the topping compound? How long do I have to wait to start texturing it? Any other hints...this will be my first attempt at crow's footing.