Usually its not a problem to use gold solder. My preference would be
medium, hard is too hot and easy doesn’t give the best control.
Years ago 6K solder was used but I found it unsatisfactory. However
sometimes GF will discolor so use a good firecoat. Best bet is laser.
You’ll want to do the least polishing possible. Sometimes GF just
goes bad no matter what you do, so there remains the possibility of
gold plating the piece just to get an even color, which may or may
not be the original color. I have run into pieces that polished out
Make sure you disclose the possible bad outcome.