IMHO (and my favorite engine builder), all dual plane intakes, as a rule of thumb, should have a pcv. The exception is a high HP engine (defined as apx. 600hp), then 2 breathers are ok. This is because the vacuum created by such a high hp engine will allow it to vent properly through 2 breathers.
Single plane intakes should only have a pcv in the intake, not the valve covers. Most single plans have the carb elevated causing velocity vacuum which will hinder ventilation. In single planes (regardless of hp) I would go with 2 breathers. If you don't want to ventilate the valve covers then go with the rear breather tube and forward filler tube by machining those openings into the intake.
...........Nobody likes
oil on their chrome valve covers!
