I can answer my self, yes the hinge is mounted on a slight angle, about 6mm lower on the outerside. The latch needs to drag the door against the weather strip when closing.
You have to care for enough space in the roof section when door gets off the latch, when the door is badly adjusted it swings against the roof (maybe my problem only).
Mercedes w126 latches is very big and not so small and neat as the more original w107 latches wiht angeld lock function.
I hade alot of problem to get the car and the hinge enough rigid so the door opens without sway. You guys that have done this proabably now what i mean.
The hinge need to go free from the wheel, free from the innerfender and need to let the door clear the front fender when opend. Now i have to figure out window mechanism and the gasstrut mounting.. Very much work with completing the doors.