I think we can get the picture.
I think the fender contour is fine, the air will follow the compound curve and it's all within the frontal area anyways. I'd look at the transition from the wheelwell to the steps and tanks.
The sun visor is also within the frontal area, but there looks like some opportunity between the doors and moon-roof/sleeper cab windows to suppress vortexes there.
Also radius the front edge of the side skirt so it underlaps the tractor's fender skirts.
All IMHO, of course.