woodwind harmonics (GDP)

[Andrew Hawryluk]

I'm trying to show how one could specify a harmonic for a woodwind
instrument (NR 2.6.1.1).
This looks correct when printed, but it's a bit ugly. Any suggestions?

Note that usually the lower (fingered) pitch is not written, but the
small circle is always needed.

{
  <c'\harmonic c''>2^\markup \fontsize #-8 " ○"
  <c'\harmonic g''>2^\markup \fontsize #-8 " ○"
  <c'\harmonic c'''>1^\markup \fontsize #-8 "  ○"
}

I wondered if the \flageolet articulation was intended for this
purpose, but it much larger than the marks I have seen in print.

Andrew