Don't laugh I'm not very technical. I have always used various things for scallops, cups, saucers, plates etc. anything rnd, placement depended on size of tblcloth or size of scallops. If I already had a tablecloth I would use it for a pattern. There r a lot of knowledgable QTs here with patterns & technical smarts who will tell u exactly how to measure & do what u want to do.. *