Airframes
Benevolens Magister
The Jagdwaffe book definitely states one quarter, and if you look closely at the B&W pics mentioned, you'll see that, with it lining up with the two blades, it is actually a quarter of the spinner, and not one third. If it was the latter, then this would take one edge of the demarcation beyond the line of one prop blade, leaving one blade totally within the white area.