White/Corbit 666 canvas arc supports and others Q

Hi there, I looking for pics or data, about the arcs or supports for the canvas of the 6 ton White 666 truck, for scratch ones for the Hobby Boss one (hard cab)

Another one, I saw a pic of one (restored?) with the front bumper painted white. But any pic of this kind “in action” in WWII. It´s a restored feature?.

And the last, Some pics show a hatch in the middle of the roof over the windshield area, or ventilation scope. Some not, any references?.