There is no correct default cd/m2 value for luminance other than the one that results in a match to a print viewed by the display under a controlled viewing booth. It might be 120, 140, 150, 123, your mileage may vary considering the luminance of the print viewing conditions have not been defined. If the print appears too dim/dark compared to the display, you either have to raise the print viewing luminance if possible, or lower the display luminance. In the same way, your white point is also going to depend on the print viewing conditions. Starting at D65 is a good idea (even better, Native White Point if available) but if there’s a color mismatch, the correct white point is the one that results in a match.