chord symbol styling

[Bric]

none of the threads discussing this lead to any solution, in my research

How do you change font-family, font-style, font-size of the chord fonts?

I have tried things like...

    \override ChordName #'font-name = "DejaVu Serif"
    \override ChordName #'font-size = #2
    \override ChordName #'font-family = #'roman
    \override ChordName #'font-series = #'bold

but that changes nothing.  Maybe I don't know the correct context these 
commands shouild be in...

my *.ly code "compiles" without error, but the chord symbols remain the 
same.

Do I need to use the full path of the fonts?

thanks