In a rather slow piece that I was listening to on nwc there were 32nd notes playing. There were some grace notes playing before it which lasting the same length of time as the 3nd notes. Also the grace notes get longer or shorter at different tempos. It seems like grace notes are set to always take a 32nd note value off the note before or after it.
True. Playback of grace notes is realistic only over a "typical" range of tempi. Also, the duration of the grace note is always the same, regardless of its apparent (visual) duration.
The best way to deal with this is to have a separate sounded staff in which you "spell out" exactly what you want the grace note(s) to sound like. This way you also have control over whether the grace note steals time from the current beat (which is the way that NWC's grace notes behave) or whether it comes in before the beat (more appropriate to some pieces).
Simon Carroll must really fond of me. This is the third post by him about me...
I'm sure it's just a crush, Grace. Must be those cute appoggiaturas.