Agree with all the suggestions...best not to try to match seams. BUT, if you do decide to try to match seams on this or your next project
, you should iron seams opposite directions for each column and "nest" them. "Nesting" means that when you place the two columns right sides together one seam faces up and the other down so with your fingers you can make them come together perfectly at the intersection. Then pin at each such intersection and sew. Your seam also will be flat at these intersections. Thought as a first-time quilter you might not know this...if you already do, please disregard! Also, in general sewing you often iron seams open; in quilting generally it is better to iron to one side or the other, as it creates a stronger seam when quilted.