vacuum lines and catch can

[tmontague]

I have a catch can installed from the vacuum line that come out of the cylinder head cover closest to the firewall and enters back into the intake.

However I cam across the topic of using mini breather filters such as this one


on the hose comes out of the front (closest to the bumper) of the engine from the cylinder head cover. This idea cam from the the thread about turbo installation but it got me thinking. "am I wasting my time by no also having a catch can or breather on the other hose that goes into my intake? I don;t want to still be pulling oil into my TB from the other hose that I don't have a catch can attached to.

Can someone shed light on what this vacuum hose does (the only closest to the bumper from the cylinder head cover) and does it also put air and oil into the intake like the PCV hose does that I already have a catch can installed on before it goes back into the intake.

My idea was the just put a mini breather filter onto the metal "spout" coming out of the cylinder head cover in the front and then just cap off the hole on the intake manifold so I don't have a massive vaccum leak. Is this a good idea to stop any other areas of oil going into my engine, or is this just useful in turbo's engines only and a waste of my time/potentially harmful?