I'm reading the instructions for the catch can install and I see that the check valve is removed during the install. I thought of 2 questions (probably dumb but I'll ask anyway cus I am a PhD (see sig))...
1. Wouldn't removing this check value impact the function of the PVC valve on the intake manifold side of the crank case when under a vacuum or pressure? So for this line that the CC is put on, instead of just sucking fresh air (at atmospheric pressure) from intake as needed, it will suck AND vent to the intake before the turbo (and with the OCC catch and oil vapour in the process) BUT thereby rendering the pcv value on the intake side redundant (as well as the breather).
2. On the stock turbo, does the breather connect before or after the compressor wheel? I guess fundamentally, is the breather meant to balance crank case pressure to atmospheric pressure or to current boost pressure? Atleast on my Hahn S20g setup the breather runs between the crank case and right before my compressor wheel (so no boost yet - atmospheric pressure after MAF sensor). See pic, ignore the lines (I was describing something else in the photo).

I still can't get it out of my head that CC's are not to correct for a faulty check value, but to catch blow by oil vapour which will still escape from the breather even with all the baffing (I've found oily film in mine). If our check valves fail (which it looks like some ppl have had that) this would call for 2 catch cans.
Forgive me if I've drummed up something already discussed, I couldn't find an answer in my searching.