Here is my solution to keeping track of a pillow. I've done this with a couple of Exped PillowPumps, BA Clearviews, and POE Ether matts. I don't notice the harness when I'm sleeping on it. This is just grosgrain, tied off, until I get it right. Then I'll cut off the span across the pillow, sew it. You could use almost anything.
This will keep the pillow right at the top edge of the matt, giving me maximum use of the rest of it. Once you position the harness on the matt and then lay down it is pretty well locked into place.