Last night I played a little bit with the settings on a77II.
The two main thinks you have to pay attention are the
-AF track duration (1 low~5 high)
Before I checked this parameters I was using AF priority & AF track duration 5 high
Now I have tested I am still using the AF priority and track duration 5 high but something new I found is you can memorise in memory recall M1/2/3 even these changes.
So instead going through menu to change parameters you can have these setting in memory recall
For some birds in fly I may try AF track duration 1 or 2 since I sometimes get he wings sharp
and the body is out of focus.
AF priority always and AF tracking duration in M1 1 (Low) M2 3(mid) M3 5(high)