Absolutely stabilize before doing anything. Then you have a variety of ways to go. You could sash everything to get uniform shapes and sizes or you could do more of a modern look with having them randomly placed on a background. This would depend on the art and the type of folks bidding on it. Be sure and take lots of pictures for her, yourself and (I'm sure if you asked her and her parents they wouldn't mind) us to see the finished work of art.