Couple of things that saved me:
The instruction mnemonic UNOS for the Northern hemisphere - Undershoot North, Overshoot South (you should undershoot the desired heading on any northerly headings (from about 280 - 080 degrees) and overshoot the desired heading on any southerly headings (from about 100 - 260 degrees)). Sketch a compass rose and think through the turn. Of course it is ONUS in the Southern hemisphere.
Acceleration causes an apparent turn toward the nearer pole.
Oh, and liquid swirl increases the undershoot, so reduces overshoot. Hence it increases the turning error through North and reduces it through South.