I fitted a flashlube catch can pro too. They are a great compact size.
Installed on a TD42, not a ZD30 but I used two plastic barbed reducers. From memory they were 19mm to 16mm and 16mm to 12.5mm.
I've got photos and details of the install here:
http://www.nissanpatrol.com.au/forum...l=1#post767863