I recommend the Craftsy course on quilting a large quilt on a small machine; it is worth every penny. I actually have 3 classes and they all recommend spray basting the quilt. Then you S-I-D from the border to the center to stabilize it. This is supposed to keep the borders from distorting.
http://www.craftsy.com/class/Quiltin...all-Machine/51 I think will take you there and here is her tute:
http://obsessivequilter.weebly.com/t...rge-quilt.html