Are you referring to the umbrella seal as oil shedder?
I hope I'm not using the wrong terminology, but I've aways referred to the tin cup as an oil shedder and the smaller rubbers seals that ride the stem as umbrellas.
Either way, I'm referring to the part referenced in the image below (not my cylinder head).
As of right now, I'm about done installing the positive seals with no intention of using o-rings or the above tin shedders/umbrellas/deflectors.
