Welcome!!! Well you may as well fill it to the top with petrol every time, it doesn't take long to get to the empty again ;-)
I can safely say that it will take 4.7 litres of oil in total, just had my first P3 service at my local Nissan dealer and I supplied the parts to get the service done cheap, it amazes me that they can charge almost £200 for a can of oil, 2 air filters, oil filter and a washer?
When they gave me a list of the parts needed they said to supply 4.7 of 10:40.