In harp scores the harmonics are notated with a circle above the note.
Since I use them a lot I decided to make a user tool.
In case this can be of use for someone else, here it comes.

N.B. Assumes font User1 = MusikDingsxxx

It is also used for bowed strings.  Thanks!

... and for horns too.
And horns also often use the '+'.
And the strings...

Ok, I just updated the tool attached to my original message (now v. 1.01) so you can optionally specify in the command line the char to be inserted.