It's not true that the factory PCV system does practically nothing at idle. I wondered how much air it would draw at idle so I put my Unisyn that I use for syncing carbs on the open oil filler hole in the valve cover. The PCV draws as much as either carb. I can't make that comparison at WOT for obvious reasons so I don't know how much it draws then.
When I first start the engine if it's been sitting long enough for the brake vacuum tank to leak down (or up toward atmosphere if you prefer), it stumbles and requires more choke till it evacuates the vacuum tank (big air tank off class 8 truck). I'm sure that upsets the PCV system for a while too but then it settles down and idles fine at about 800 RPM.
