You're best bet is at auction since it provides the highest flow of equipment. Craigslist is another option as a seller there usually gives you an inspection option. Last but not least is right here! Bartertown is available for subscribers as it is a hidden forum but by subscribing you will gain access to members' buying/selling all kinds of stuff.
Regarding auction items, the level and quality of restoration is always suspect. Always. And always factor in the cost of shipping as well as tech fees if you're not going to do it yourself. As far as a tech is concerned, there are quite a few very competent folk that restore Fisher equipment. The "best" is a subjective call depending on baseline skills as well as the workmanship quality of what is done. There are the speed demons who snip and tack components, and there are those who desolder and properly wrap components before soldering. For my money if I had to send a piece out for a complete overhaul, I wouldn't hesitate to send it to Dave G. who, by the way, often hangs out in this forum. I have no idea what his queue is like but you will be absolutely satisfied with the work.