When you print your first copy, check to see if there is any distortion. If there is, use a pencil and recreate the lines so the block is square. (Sometimes the printer will distort lines slightly.) Check your first printed block from that copy, if it is fine print them all. If you do this and take your time to carefully sew on your lines, then don't remove your paper til completion of the quilt you will be fine and squaring won't be needed.