[aerohead]

From what Hucho shared in his chapter on commercial vehicles, and NASA's reporting, the Daimler-Benz Freightliner would have the advantage.
Daimler's design blows a bigger hole for the box to trail behind, and that added width and height better takes more of the leading edge hit, than the horrible face of the box.
Ideally, the cab would be just as big as the box, as with Tesla's Semi/ NASA's semi, most current Class-8 rigs operating at a profit.
It's the difference between Cd 0.89 and Cd 0.41.