Well, a quilt top measuring 90 X70 = 6300 square inches. Your strips are 5" wide, so will yield a strip 4.5" after you deduct the seam allowance. 4.5" X 40" for width of fabric gives you 180 square inches per strip, assuming you use the entire strip, no additional seams. 28 strips will be only 5040 square inches. So there is no way that you can arrange the strips to make a 90X70 quilt top.
Sorry, I don't understand the 2 strips by 14 arrangement...
Last edited by PaperPrincess; 09-23-2014 at 01:21 PM.