There's another book that is really good too. It's called "Taking the Math Out of Making Patchwork Quilts" by Bonnie Leman & Judy Martin. The ISBN # is 0-9602970-3-0. It gives you standard measurements for different mattresses, etc., helps calculate sashing for straight sets, and calculates how much fabric squares, rectangles, and isosceles right triangles, hexagons, etc. take. It even tells you when to use each chart.!! In all, it has a lot of info for planning quilts. So it would answer the question about reducing the overall size of a pattern. Hope this helps.
Virginia