What about using the oil cap hole in the valve cover to vent, you could use a pressure release valve that opens at 10psi pressure or a solenoid valve and pressure switch that opens at a certain boost to release crank pressure.
Are you still running the air flow meter? because the vacuum of the intake pipe before the turbo can be used to suck some of that pressure out but if the AFM is before that point you'd be sucking in un metered air...
I would guess you are running you 4 hole PCV system independently/un-metered. So controlling oil from leaving the PCV system would be the only concern. You could put 4 small filters on your current holes and run a pump off the oil cap hole.
Are you using the factory turbo oil return on the block? you could run a hose and catch can off that and vent some of the crank pressure at the source.
With the amount of pressure your crank creates, oil must have a hard time draining back to the block under boost.
What symptoms does the crank pressure have? High idle after boosting? Dipstick pops out?
Off topic, meth injection question.
I know the basic calculators and so on for water meth... but I am running it only above 16psi, I am thinking of running 100cc per PSI from there on.
So at 20psi I would be running 400cc's, any thoughts on what ratio I would want above that cc's to PSI (maybe 10-12whp per psi at that boost) but the factory intercooler I am running is corroding and too small and heat soaks above 16psi in hot weather, so the water meth is heat suppression until I get a bigger intercooler on the car.