I saw a technique on Overhaulin' yesterday......they hung the door with the front fenders removed so that they could more easily get to the hinge bolts. They got all the gaps where they wanted them and then they drilled some small holes into the meaty part of the exposed hinges....presumably so that they would have a reference hole to "pin" once the parts all came back from paint. Just line up those small holes with a nail or whatever, and the door would be just as perfect as when it came off. /forums/images/graemlins/thumb.gif
The other thing I saw them do was to actually weld on thin strips of 18GA? metal onto the lower doorskin (or wherever) in areas where the gaps were inconsistent. I think that once you get the major "style lines" all lined up and the door latch working right....the other gaps just need to be filled, or filed, or welded to make them right. The factory fit and finish probably wasn't that precise to begin with.
I'm not an expert, but that's what I saw....and it seemed to make sense to me.
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