I would consider using a stabilizer that you sew around the edges of the fans, and then turn them inside out. That would put all raw edges to the inside. Then you could use any stitch you wanted to frame the edges. Sometimes, simpler is better. I'd practice on another fan and see what you like. I would not use rick-rack. It is too bulky and works great for straight edges, but not so good for all those points. I would choose a center medallion color and do the stitching around the fans in that color, or in the darkest color you have in the quilt colors.