I usually press to the side when constructing blocks unless there is a specific reason to press a few of them open as per instructions. When I am ready to quilt on my DSM I stabilize the whole piece by stitching in the ditch lengthwise and widthwise between each block. Then I go back and quilt each square or row when it is stable. I don't quite understand how you would do this stabilization if the seams are pressed open. I have never had trouble quilting the piece.