Yes, I would SITD and also stitch the edge of the quilt before doing the border. When I did hand calligraphy and something needed to be centered, I would write out the line of text, then fold the paper in half to determine the center of the text. You can do this to find the center, however, I think I would start on the ends. Are you planning on using hot pink thread? I'm wondering if white will show all your hard work.