.........Several (or many) degrees, error in directly pointing at the sun is not going to make any measurable difference to the collection of incident solar radiation....
KISS.... comes to mind..
Dynamic biaxial tracking is ideal,, but surely, not necessary.
I have an array that I adjust for season..
My main Grid Connect system is seasonally adjusted, for angle-of-dangle..
I can't see any incremental difference from one step to the next.
I do see the difference from one extreme to another..
........Simplest possible system would have to be a propane mass weight transfer tracker.
Next step up would be a SINGLE AXIS dc motor driven optical self seeking tracker...
So, were I experimenting with a tracker, I would start with a seasonably adjusted elevattion and linear position control..
KISS..... we know what time the sun will rise and set..
So a simple direct drive control for time of day... no cloud issues, no edge effect causing false bright spots..
So, with KISS in mind, what percentage difference would you get by using a super accurate biaxial controller.???