In my opinion, there is no need for an additional aftermarket catch tank. If you are finding that your intake lines are loaded with oil, I would check that the 1-way valve (Number 7 in the diagram) is functioning properly.
Disconnect it from the plenum and try blowing through it. If you can blow through it with minimal effort, it means the valve is no longer working and any positive pressure from the plenum will result in oil being blown out of the catch tank and fouling your intake with oil.
If the valve is functioning properly, it will help draw out out oil vapors from the cam cover when the plenum is under negative pressure (vacuum). Condensed oil vapors are then fed back to the sump.