I've just done a quick route plan on Runway HD based on Perth 21 runway at 60 knots. Current wind is 250/15. Magnetic track is 222deg. Which would amount to a crab angle of 12 deg.
This app uses true track converted to magnetic heading so is 3deg incorrect.
All that is required is the runway magnetic track converted to current wind corrected mag heading at landing speed. This would be done well before final.
Alternatively. Know in advance what the pilot's or aircraft's max crab angle is and watch the compass/DI on final for excessive difference to runway heading, and go somewhere else as required.
Faffing about with mental arithmetic and charts on final is nonsense.
I've forgotten whether runways are in magnetic or true, or is that wind directions?