Beautiful scrappies! The first one looks like my Spiderweb quilt and I did press the last seam in the middle open. I found when I quilted it, it pulled the seam enough that you could see the thread. I ended up having to sharpie the grey thread in the middle. I think it is going to be a choice between pressing open so it is easier to quilt though or doing the center swirl technique and hitting it with a rubber mallet so pick your poison.