After draining stick in 2 litres then top up on your hands and knees whilst looking at the glass sight window, start her up for a couple of mins then leave for 10 and top up as required.
Note the upper level isn't the top of the sight glass but the upper mark on it!
Official is -2.5 litres standard oil change
2.7 oil and filter
And if you're interested 3.5 following a full engine overhaul!