Gorgeous fabric! How big are the blocks? Are you making a lap quilt? If you have 10" blocks and add 1" sashing (one of the darker colors or black) and then a 1" border after you sew the rows together, the quilt will then be 34" X 78" if you go with 3 across and 7 down. With 4 and 5, it will be 45" X 56". You can always make the border or sashing wider or put on an extra border if you want it to be larger.