I'm a hand quilter and press my seams open all the time. Just like the accuracy and flatness I get to my quilt top. I have done SITD but even with open pressed seams it's HARD if you quilt in the actual 'ditch'. I use W&N batting all the time. Because I want my quilting to show, I usually do 1/4" away from any seams as well when I do that type of quilting vs. an all-over or design-specific quilting pattern. I've never had issues with SITD with open-pressed seams though.