https://postimg.cc/gallery/jzniiriy/
OK, I included a link with build pics of my Aerodyne. I checked the gaps on my Aerodyne with one screw spacer under each cab mount and I'm seeing about a 1 mm gap between the bumper and the fender, and a 2mm gap from the top of the cab to the aerodyne cap. There's a pic of the front bumpers of the 85 KW and of my latest project the W900 Studio Sleeper with a 4mm spacer lift. I wanted body flaring under the cab and sleeper for lights but covered them with chrome step trim. I added flaring to the front lip of the fender to close the bumper gap and purposely left the space under the grille open. if separating the Cab and sleeper you can also elongate the bumper mounting holes to raise it up, which I may do. This only works if using a aluminum bumper as the stock plastic bumper has the molded slot for the bumper mount.