Crankcase Breathers Options

[McMark]

I was looking at the factory manuals and talking with someone about crankcase breathers. We were talking about breather setups for carbs specifically. And I realized as I was looking at the breather diagram that it appears that the breather ports on the heads were included to supply extra air to flow through the engine case. And then I read this little snipped in the manuals which seems to support my thought:

Crankcase ventilation has been considerably improved in the engine by ducting fresh air from the air filter. This modification reduces crankcase condensation and icing at low outside temperatures.

So following that logic...
If the crankcase breather (at the oil filler neck) isn't connected to a vacuum source, then the ports at the heads should/could be plugged instead of connected to a breather box.

Thoughts? Contradictions? Agreement?


I realize people have been connecting breathers all sorts of different ways and most work just fine. I'm more interested in the theory aspect, and refining an 'ideal' installation since we already know many ways to 'make it work'.