Since the designer has advised you, and you have the wealth of information of some of the best quilters on the planet you should go ahead after viewing the video. I have a scallop ruler and it has been one of the best investments I ever made. If the scallops are a tad smaller in one area I am of the opinion that you will be the only one who knows. Your quilt is going to be absolutely beautiful, be confident and you'll triumph. Just talking about this makes me want to go down to my sewing room, but then just about anything makes me want to do that.