I'm certainly no expert - have not yet attempted a scalloped edge binding. But I do know that I've read several times that the binding for scalloped edges should ALWAYS be cut on the bias for be best results. There is a really good tutorial out there somewhere on cutting bias binding - it seems a bit complicated at first, but after reading the instructions several times and following them carefully it isn't difficult. And you can get a LOT of binding out of not too much fabric. I just did a 60 x 60 and used only about 1/2 yard of fabric. Wish I could find the link to the tutorial for you - I know I saved it somewhere - just not sure where.