Might you show us a factory system that vents anywhere except under the primary intake source?
I believe you've taken a generic statement and assumed that it'll remain true in multiple intake system. What they said was true about the effect when you introduce the PVC leak under the primary intake source as it can be compensated for through a slight richening of the carb or injection at idle. It is true that less goes through at idle, but as very little air flows through a closed throttle at idle, it takes very little to change the air/fuel ratio.
Take a look at a '60s Chev 8. The PCV valve is located at the back of the passenger side valve cover. The line is run forward and tied into the carb under the primary barrels. Why make it so complicated if it doesn't matter? Take a look at "factory" multiple carb systems and see where the PCV is tied in. Look at a 194/230/250 intake and see how they've gone to the trouble of runing the PCV tube through the intake manifold and up under the carb to that the PCV leak ends up mixed with the incoming A/F mixture equally so as to not lean out a few cylinders. If the tube wasn't there, and the PCV leak just entered in line with 3-4 cylinders, you'd have to run 1,2,5 and six rich to avoid the lean misfire in 3&4. I wasn't trying to be a smart a$$ or putting down your work, but trying to help you avoid having 3 rich cylinders at idle and cruise.
