Hi, I would run a line of stitching along that top row to prevent fraying. I have also used the blue painters tape on my fabric with great success and it is very inexpensive. You could put it on the front then over the top to the back. Just be very careful when taking it off. I use the 1" roll. I use it to tape the back to the table, cut it into small strips to mark my ruler, audition placements and block arrangements and more that I can't think of at this hour. I'm sure others have great ideas too. You have quite a task ahead of you. I'm sure it will be absolutely beautiful! Happy stitching.
Wendy