Never mind WW2 - it wasn't much better in the 50s. On the navex flown to qualify for a BC Select rating, the requirement for a Canberra crew on the long 'limited aids' (ie astro) leg was to stay within 50 miles of the intended track - I don't remember what was called for on timing. It did make you realise what a godsend the introduction of Gee must have been.