I love the vintage machines, and teach my quilting classes using a vintage FW. I will be teaching a class in the Spring on maintaining your vintage machines. It's really not hard to do, once you know what to do. I agree that trying before you buy is a good idea. Even if I'm just selling a presser foot, I want you to make sure it works on your machine before you get it home and maybe have a problem.
Good luck with your search!
Stephanie in Mena