change metronome size

[plutek]

does anyone know how to change size of a metronome marking?

this changes everything, except the note stem (which stays as it was both
in position and size):

\notes { \property Score.MetronomeMark \set #'font-magnification = #0.5
\tempo 4 = 120 c''1 }

this doesn't seem to be addressed in regression or tips, and the only
thing i could find in the list archive was from years ago, before \tempo
existed.

thanks!

-p