Gearbox oil cooler

[Eddiemex]

Fitted a Mocal laminar flow oil cooler and was wondering how much oil I should now run in the gearbox as there will be some extra capacity in the oil lines cooler and pump. I also thought I read somewhere that some of you run about 3 litres in your boxes. Anyone have an idea?
My Nob is a 3r by the way.

[GTO600]

All I do is fill the box to it's normal level then run the pump so that the lines are full then switch off & top back upto the level again.
Kevin