Dear Auguisto,
A very nice build.
Technically certainly very well executed.
However: historicaly at least doubtful.
Why?
Since the use of enemy markings and uniforms is a very serious war crime, the 'americanised' vehicles were kept in very high secret, even on the Axis sides ( due to the enormous amount of PoW's the Allied forces made every day, only the shear suspision, based on statements from German PoW's, would have created an enormous alarm along the entire Allied front.). Thus reducing the effect to zero. Therefore, these vehicles, as well as other captured British and US equipment, were only used on the first day of the German attempt to break through in the direction of Antwerp. (The offensive was called Operation Greif (Operation 'Attack'), pls., have a look at the web for more info.) The machines would have had a rather unused, new look.
Nevertheless: I like your techniques
P.