I did a king sized quilt using Marti Mitchell's Quilting in Sections (I think this is what you are referring to?). I quilted right up to the edge of all parts. The sandwich would be backing that is larger than the center and borders will be. In other words, as large as it would be using a regular assembly system. Then I added the borders one at the time using the flip and stitch method thru all layers (top, batting, backing). Then I quilted the borders. I'm not sure that's exactly how she recommends, but it worked for me.
My center was 4 pieces so that was another adventure
