I tried my Zircon stud finder on it`s metal scan setting to see what it would do. It couldn`t fully detect a 1.5 inch finishing nail through five eighths plywood. Some of the lights lit up but not all. It had no trouble when I laid the nail on the surface so I think it would be good with a nail that was just under the surface.
Someone I consider a master woodworker once told me that a master woodworker is not someone who never makes mistakes. He is someone who is able to cover them up so that no one can tell.