I just learned this method last week and my geese came out perfect! I don't know about adding and trimming, but you need to use 2 x 4 as your finished size (without seam allowances). So--for the geese: 4+1 1/4"= 5 1/4" and for the sky 4 squares that are 2+7/8= 2 7/8". Mark the center and the 1/4" on either side of the cutting line and sew a scant 1/4".