I am using one also although a bit more conventional then Marlin's.
You can see the catch tank on the left. It has two lines, both stainless hard lines. One comes from a vent on the left valve cover and the other goes to a vacuum manifold that is hidden in this picture under the header heat shield.
The tank has an external clear/tinted tube that will show you the contents of the tank and there is a petcock drain on the bottom.
In all honesty it doesn't catch much oil per se but does accumulate mostly water.
The system isn't as much of a catch tank as it is an oil scrapper.
My Audi TT turbo has a very similar set up although much more low key and winds up with just about the same level of water and sludge. It really never gets to the level of needing to be emptied. So you really can't prove the necessity of needing a scraper system like this BY ME...BUT YOU ASKED!
