I am still having trouble with my borders being wavy. How many inches apart do you pin. I pin probably about every 2 to 3 inches. Could my strip not be straight? I know I'm suppossed to measure and then cut but everytime I do that I end up with too much or too little - somehow. So I go ahead and pin until I get to the end and then I fold back the excess, iron it and then cut on the crease. Is this causing my wavy borders?