For unlevel ceilings which creates oppressing energy at the lower end of the ceiling you can also hang two flutes at 45 degrees each (again mimicing the top half of the Bagua) on the walls directly beneath the edge of the oppressing chi from the ceiling.
To ensure Chi coming in any of your doors is nourished, hang a flute horizontally on top of the door (inside the room). This is especially useful if your garage directly links to your living room or kitchen. The bad Chi from your car engine could be detrimental to the Chi that directly enters the doors to your living room or kitchen. The flute will also provide protection against negative harmful energy such as burglars.