I have several questions:

1. How big is the array you're trying to move?

2. What form is it? A flat array, a half cylinder or a true parabola?

I have seen a scheme wherein two solar cells are connected in parallel opposing and are screened by an opaque panel. The cells are arranged side-by-side in the horizontal axis. The panel is raised above the cells enough to uncover one cell completely when the unit is rotated away from the sun by more than 45 degrees. The solar cells are connected directly to a small motor that drives the main array. The whole thing is mounted on an equatorial mount positioned to split the difference between the summer and winter elevation of the sun. That's a sort of long winded way of saying that the system is self tracking and self positioning with NO external power. The size of the motor/sensor panel set is determined by the mass of the main array.