So, I tried a different sketch, and it works more predictably.
I need to go over my adapted code, and find the problem.
When I run this sketch, the tracker seems to have exagerated jitter/oscillation randomly.
Maybe somebody can spot the problem ?
:-?
EDIT: Ok, maybe it needs a center position to start:
void setup()
{
ServoHorz.attach(servoX);
ServoHorz.write(minPos); //Quick Initialization before start
ServoHorz.write(maxPos);
ServoHorz.write(output);
delay(2000);
}