When connect to breather, which is located at the right side nearer to intake hose. This type of OCT setup may not capture as much oil from the rocker cover because the breather was a 1 way valve, provided intake hose vacuum is not as strong as intake manifold, therefore a very small amount of engine oil get suck out/captured in the OCT. However, this setup allows maximum cleaning effect to throttlebody.

Connection of PCV breather, which is located at the left side of the engine nearer to timing belt. This type of OCT setup will suck out more engine oil from rocker cover. Reasonbeing the intake manifold has stronger vacuum. If you have a loosen oil channel, result in huge amount of engine oil being channel to the top part of the engine, this setup will allow extra engine oil being suck into OCT instead of going back to intake manifold and sent to combustian chamber. If your engine not in good shape and needed to sent for puspakom inspection, this is a good way to cheat inspection. No engine oil going back to combustian chamber, no white smoke. Regular maintenance of OCT is required for this type of setup. Very suitable for cars that gradually reduce engine oil/white smoke cars.

Why I choose breather instead of PC valve? Simple, car is new. Hardly any engine oil being sent to combustian chamber. Only time engine oil might flow out through breather/PCV was WOT. I want the OCT to prevent my throttlebody being too oily rather than having some smoke when pedal to metal. And ofcourse, if you want fully eleminate engine oil being sent to combustian chamber, it is better to have 2 OCT to capture oil from both breather + PCV.