Was finally able to get some real footage using the
3D printed seat post mount. here is a one minute clip from Jan 19, 2015:
As you can see it is as stable as any other commercially available mounts out there. If I had more time I would have made this a bit more than just video. At the fastest section of this clip we are traveling just about 20 mph (its winter after all).
I do know that the rear tire is near the end of its useful life.