My two cents..
I have been working in two different enviroment. The first part of carrier without airspace classification ,i.e. each a/c regardless of flight rules was separated by 1000ft/300m(whatever is more applicable) or any other ICAO based minimum.
Later we "dicovered" airspace classification and we felt like "new born" . Since than, no separation were applicable in classes D,E,F,G , between IFR/VFR.
But you always have to have some "personal" separation. IFR departing on SID and VFR orbiting on rwy hdg 2Nm at 1000 ft. It si not mandatory to separate them but as my friend told me " I would separate them due to religious reasons"
