No way a PCV type valve can create a vacuum in the valve cover under any boost..
I know, it's not supposed to, it closes under boost. The PCV only creates vacuum in the crank case when you're not boosting. As you mentioned.. there's lots of info on DSMtuners about this. Venting doesn't work as well as sucking out the fumes.
By what you're saying, I don't think you fully understand how the stock system works.