I have reduced the volume of harp notes to reduce the obvious 'plinking', although I didn't find it was so much in the upper part of the top octave, I found it was actually G or ^G. I've had a couple of songs I've done recently where they really bugged me too but wanted to keep the harp, so went through and turned the dynamics down for just those plinking notes.
Haven't worked much with the pibgorn (yet. I have one or two things in mind for the future > ) so can't comment too much about it, and if anything it's the flute and clarinet that I find you have to be careful with. The high flute notes can be so piercing if too loud and held for long notes, and the clarinet's tuning in the upper register is by no means spot on.
*sigh* So many things need attention with the music system, I can only hope it will be like the housing and finally get some attention after lots of years with the player base demanding it.
[color=#58732A]~The wind is full of a thousand voices~[/color]