i built a catch can, it didn't catch nearly enough of the vapors, and made a mess.
routing the vapors directly into the turbo intake was much better for me.
no more mess, no more emptying, the cylinders are full of oils and gases anyway.
i appreciate the ingenuity of the catch can but i'm not convinced that it's needed.
here is a picture of what i believe is a '79 300SD with the same configuration:
