I have some questions. To put my blocks together I need to cut pcs. about 3" wide as long as one side of the block. Sew together with 1/4" seam and press seams open, Correct? (Oops I forgot I lay the blocks out the way I want them to look and then do the sewing) oNce I have this done I measure how long a strip I need to join each strip of blocks correct? Then do I use the same material for the backing or do I use a colored sheet? Thanks for any pointers..