How many pieces are in the layer cake? If there are 40, you would have 80 squares total. Each square will be 9.5" finished. So...maybe 8 across and 10 down--with no borders, the quilt would be 76" x 90.5". A full size batting is 81 x 96" if there are 42, setting them 7 x 12 would result in a quilt that is 66.5 x 114, which is an unwieldy size.
Last edited by Krisb; 08-24-2012 at 02:27 PM.