Using a longarm and standup frame I would SID the top border, then quilt it (this would stableize the border and keep it nice and straight for the quilting); move down through the body of the quilt either basting or SID around blocks until I reached the bottom border. There I would SID the border once agin before quilting it. Remove and turn the sandwich 90 degrees, SID and quilt the border; move down through the body of the quilt, finishing the quilting within the blocks, to the bottom border; SID, then quilt the last border. Just the way I do it to keep the quilt as square as possible. I'm sure you will find what works best for you. Happy quilting!