I start every season with min bonus and in league keep it that way unless I get into a tight spot at the end of the season. In cup and CL I increase it step by step when I reach knock-out stage, based on opponents strenght and results. In finals my bonus is maxed.
No idea if it works and, if it does, having set a high bonus ór increasing the bonus has the most effect, but if it does I want to profit in both ways.