View my video of how I planned to teach this here.
This past week was our first experience trying to see how kindergartners could handle all the steps, concepts, and button pushing necessary to do this technique. It took every moment of my 1/2hr art class to walk them through the steps from turning on the wifi to importing the saved image into the Brushes App, but WOW they did it! I don't know how I would do this without the Apple TV. I need to walk around the room, demo, and show my screen all at once to do a really good job and Apple TV's ability to mirror my iPad exactly is perfect for this!