I adapted a method taught by Harriet Hargraves when I pinned the Signature quilt. I have pictures here:
http://quiltingcorgis.blogspot.com/2...-ye-unpin.html
Basically - I centered the quilt back on my big board and locked in place with binder clips (bought specifically for quilting, and cleaned in advance so that I don't transfer anything to the quilt). I then centered the batting on the board (the hardest part for me) and then the top.
Because I was worried about things being consistently centered along the board, my addition to the process is to tape coffee stirrers along the center length & width of the board so that I can feel the lump and ensure the centeredness. I also used a ruler to be certain that the front of the quilt was precisely centered on the line.
After pinning the center, I released the binder clips and let the pinned section hang off the board to the front then repinned along the back of the board - the weight of the pins kept the tension in the quilt. I repeated to the other side.
The one thing I will change next time is to use a solid surface to pin against. Using the big board, I pinned the quilt to the fabric cover more than once Even putting my cutting board underneath would improve the process as the pin would have something to work off of, rather than get caught in.
Hope this helps.
Cheers, K