You mentioned the leaky rear main seal. One trick is to put a vacuum on the crankcase. You are then sucking minute amounts of air through the seal instead of bleeding minute amounts of oil out. One method (prescribed by Ron "The Gadgetman" Hatton) is to cap the breather side. This forces full engine vacuum on the crankcase through the PCV valve. If this scares you, back in the '90s I tried an En-Valve (still around last I checked) that puts a regulated 5" of vacuum on the crankcase. The one downside to the En-Valve is that it bleeds ambient air into the system, not filtered air.
Something I did was to get a vacuum regulator valve from McMaster-Carr and place it on the breather side. Putting a vacuum gauge on the dipstick allowed me to dial it in at around 7" of crankcase vacuum.
More on PCV mods.
