Anybody running 17" Cobra Bullit rims on a Duster

Anyone have a diagram pointing to where the measurements are taken? Drum to drum? Is that the flat front face of the drum where the back side of the wheel interfaces? I am dealing with a narrowed C body rear end and axles that is quite nicely done but appears to be barely wider than normal A body on width. Perches appear perfect though so I am good there.