So, here it is now, with the stitching in place and a bit of cropping - the full piece above.
Below, I have two detail shots to show the stitching.
I use this free motion zig-zag quite a bit in my work. I do think this is the look I am going for on the other piece. I am not looking forward to it, though - it is tiring for me to do this repetitive side to side motion in order to create the EKG type lines.