I have flown my long with and without a seperator. Presently I am operating without.
I have run a metal line clamped to the exhaust that I use for the vent line. This
burns up any oil that might blow out and leaves a bit of a smoke trail.
For me, the biggest thing I have found is to not overfill with oil. If I top it off to 8 quarts it will blow out 2 very quickly! It will run at 5.8 to 6 qts. for HOURS.