Crankcase breather question

Lol i knew that was coming, reason im asking is because there seems to be so many pcv valves out there how do you know which one to use? I have a generic one now from the parts store. Only seems to be either closed or open when i sucked air through it using my mouth.I am running stock valve covers with baffles and i noticed some oil residue on the pcv valve nipple. How do you know if your getting too much oil through the pcv valve? Naturally theres going to be a light oil residue in the hose right?