Another idea for the singing table. Have several file folders, the kind that you open, on the table. Something like hanging file folders.
*The folders are prepped with very fine sandpaper glued inside.
*A"window" just a little smaller than what will show in the quilt, is cut into the front flap of the folder. (An exacto knife works here.)
*The helper puts a piece of fabric (larger than needed; just a larger seam allowance) onto the sandpaper in a marked area; close the front of the folder and the area visible is the only place in which the guest can write.
Have fun making your quilt.