Regarding castle nut torque, as you mentioned, tightening torque of nut is 290-390N/m for FE model on Fuso specification.
I’m not sure whether I give a precise answer to your question, however,
If P/shaft hole is not fit with castle nut dent when tightening nut with required torque, you can install pin from next dent.
Even you tightening nut a little bit more(to next dent), you don’t need such a strong torque. 100 torque range is enough.
We think there is not much difference whether it is 2 holes(every 180 degrees) or 4 holes(every 90 degrees).
For more easy understanding, I added some comments on your file.