Using dual axis solar tracking is a good idea but controlling the Altitude motor with respect to sun has very little benefit as compare to Azimuth control.Let us see the following figures for explanation:
The position of the Sun in the sky relative to an observer on Earth is defined by its altitude angle α (solar elevation angle) and its azimuth angle Ψ. The sun moving from East to West and the this angle we call it Azimuth Angle. The sun daily cover this Azimuth Angle. However, The Altitude Angle of the sun is changes throughout the year with a very very little increments during the year days.In winter the sun is more toward the Southern side and Altitude angle is small . Whereas in the summer the Altitude angle is on the extreme and sun is just traveling at the top of our head;)..
Here is the micro-controller(ATMEGA328P) based single axis Azimuth control circuit with East-West limit switches. In future i shall explain how will this work.