I had to put one of the new boards to the test, so I built a rugged tracker that can have several devices mounted to it.
The base is a piece of plywood, and the horizontal drive is a gearmotor driving a large spur gear.
The spur gear is attached to the base, so the gearmotor rotates with the upper assembly by riding around the large fixed spur gear.
This system allows a strong bearing on the main horizontal axis, and does not expect the motor shaft to carry the assembly, it only drives it.
The vertical drive is built the same way, and is a large aluminum angle frame that the devices to track will attach to.
The sensor PC boards are mounted to the side of the frame, and can be easily adjusted if necessary.
The amplifier has lots of gain, so we must adjust the gains so the tracker accurately follows the sun, but not so much that it begins to mechanically oscilate.
I built up a custom solar panel that can output 650MA @ ~10-12VDC, which should easily power the well balanced device.