here are a couple of links that may help you... if you use the copier to reduce the size, subtract the seam allowance first, reduce the percentage, then add the seam allowance back on
http://www.quiltmaker.com/articles/R...ocks_Worksheet
http://blog.shopmartingale.com/quilting-sewing/quilt-math-how-to-reduce-and-enlarge-quilt-blocks/