Okay, here's a tip as to how we managed to hang these without scaffolding. We cut wholes under the flagged pieces at the top of the large cornice, used two 20 foot extension ladders, grabbed that baby and carried it up. After placing it on angle irons that we put up earlier we reached through the whole and tightened the screws.
When the room is this large and the ceiling height measures 20 feet you need large statement pieces. In order to keep the statement pieces from being so bold as to seem as though they pop off the wall you can tone down the effect by using a soft neutral colored fabric. Then add a little bit of detail with an accent fabric.