"The best you can do is get the error spread out as much as possible" ... I like that. My reply would have had more four letter words, but yours is nice.
I had a body man in the family - It still wasnt cheap. But he got things verrry close. It helps having someone who knows how to adjust things, and some things you just cant do yourself. We're still not done - will have to elongate some holes.
The other thing is if you are using repro parts, they dont fit for ****! And no two parts are the same. I had fenders fit perfect with no adjustment, and others you cant adjust enough.