Here's my 2 cents on this.
First off this is not criticism. Greg K is one of the most successful Gadgetmen ever in terms of result's achieved on a personal vehicle.
The immediate thing to deal with is what to do if water/milkshake goo shows up in the crankcase, after a PCV re-route. This obviously is aggravated in cold or wet weather. Cold increases condensation, wet weather adds water vapor in the atmosphere.
So, you can add a water separator , but this works best if there is active crankcase evacuation (the stock PCV system).
If the re-route , or filling/plugging the PCV valve have been done, and then the water/goo appears...What I did on my '85 Subie was to restore the PCV back to stock, with a change. I added restriction in the hose between the PCV valve and the man. vacuum port. I put in 2 pieces of hose-in-a-hose into the PCV hose. By looking and playing a bit with various kinds of hose- fuel line, vacuum line, windshield washer hose. It's possible to create a restriction in that hose. If not familiar, go look in the auto parts store at hoses--you will understand easily. Each engine and vehicle will be similar, and also unique. Restrict the hose I.D. down to 1/16 to 1/8" inch. The I.D. of windshield washer hose is about right. There's lots of this hose on most every car in every junkyard...
Be creative, this ain't Rocket Surgery!
I also use an air/oil separator setup in the PCV hose, and it works great. I simply made a bigger catch can to extend drain intervals.
The restriction method is a compromise. You give up some of the benefit of the PCv re-route, but control water condensation in crankcase. IF your own car, or a customer you can work with. you can even set it up to be able to switch between the restriction, and full PCV re-route.
Another way is to add a valve in the stock PCV valve hose/line. Normally kept closed to block vacuum, if the water/goo shows up in crankcase, crack it open 'till warmer/drier weather.
Tracy G