Px- Generalising a bit, but N polar directions - rwy, sfc winds, en-route tracks and winds are all true. Certainly in Canadian Northern Domestic Airspace due proximity of Mag pole. Russians use T up that way as well I think. Alaskans stay in M because its not that much of a factor.
Polar Tracks are all T even when they start at low latitudes. The transition points, M to T, will vary with routes being flown.
In the lower lats, rwys, sfc winds given by ATC, ATIS, enroute tracks, headings are mag. Volmet, forecast sfc winds, metars and winds aloft are T. This last item is a favourite check question for those new to transatlatic ops "What`s the X-wind component on rwy X @ Y ?".
Down South, do what you like. US Mil will almost universaly use Grid for everything. Antipodean Mil as well. Brits will use Mag cos they generally don`t get near the Magnetic S Pole, but winds aloft ? - pick a datum. Around these parts 3 identical a/c could easily fly the same ground track with 3 completely different headings (as they could anywhere else if you ignored the conventions ).
Sorry RevStar if this is more information than you needed.