The next step was to fabricate a new piece of inside channel with the correct profile. Fürsten had a sample laying in the work shop, so I used this to find the shape. And it turned out perfect =) Now the alignment was close to perfect, but the corner was far from solid. Making the rounded piece around the heater tube was no easy task. But after a little trimming and adjusting, the pieces fell together. After welding everything up, it felt more solid and looks straight. It's probably forgivving to weld on a VW T1, as many of the lines on the lower body can be meassured out from straightlines, and nearly everything has the flat bottom of the car as a reference point.
I decided after starting the welding that the Veng part was no option in this corner. The shape was not anything near the OG shape. So I wnt for a total fabrication of the pieces myself. And it turned out better than expected. I had to skip the dimpeled part with the two holes for the bodymount, but in my eyes this is a small detail missed compared to welding in the Veng part with totally wrong shape. Maybe I can fabricate the the correct profile after everything is welded in place?