My preference would be:
1. On the ground pre-flight - measure tracks in true, use true W/V, add variation, obtain planned mag hdg.
2. In flight use mag hdg and mag trk for the reasons stated above. (Unless using true on oceanic flights!).
3. If you need to measure a track on a chart in flight use the nearest convenient VOR rose and the edge of the checklist as a 'parallel rule'. Actually easier than it sounds!