I've come to the conclusion that there are basically two ways to get a restoration done by someone else. First is you go to the most reputable places like Van Dijk, Kienle or the Classic Center. Then you are sure the work will be done very well (although from experience even there I can say maybe not entirely right the first time). You also know that you will pay the maximum price. A few years back, a full restoration of a Pagoda in ok shape to begin with would cost approximately €100,000, or $130,000. These days, it is probably some 20% higher, I don't know. Combined with the cost of the car ($25,000?) this results in a total cost that the owner is highly nlikely to ever recoup. That's why I said "about half".
Then the second way is to not use the most reputable places. Then there are two extreme variations: the ones who take pride in the work and do it really well, but cheap. And the ones who do it poorly and equally cheap. For example, when I needed a new floor and a few other things for the El Camino in 2011 I went to an ok place in Geneva, who quoted me the equivalent of €7,000 for the work. I ended up going to a tiny shop in France, who did it for €1,700. I visited several times and they made lots of photos, and I have seen other work they have done. It's really good work.
So the challenge is, for those not wanting to go to the top-dollar places, distinguish between the very good and the not so good places. But a good restoration does not have to cost top dollar.