If you plan to do all SID first, start in the center. That's where the most fullness will live and where the eye focuses first, so it needs to be flat and symmetrical. The big issue with this is what happens to the rest of the quilt when you start in the middle. You'll need to float it, so secure the top edge of the top with pins (don't stitch it down because you may need to re-position it later). Then advance to the center, smoothing as you advance. When you reach the center, adjust so it's symmetrical then stitch baste or pin baste horizontally above and below the center. Then baste the enti