The Haynes manual is correct. Filtered air goes into the engine via the air filter box into rocker cover and comes out the block breather to a PCV valve where it is directed to the balance tube and burnt.
If you want yo keep a PCV system with triple webers, you need to tap into each of the runners to keep it even as there is no balance tube. According to PMC, sealing of the rings with the negative pressure is not necessary and it can all be vented to the atmosphere.
Get a catch can and plumb both rocker cover and block breathers to it and have it all vented so pressure does not accumulate.
Google images has tonnes of pics for mounting ideas. Apparently steel wool in the can helps oil vapours condense and stay in the can. As Dak2kman said, do not plumb back into engine.