Hi @michaelstarobin, you can adjust the playback for the grace notes very individually, using the Played Duration view in the Key Editor.
Here an example with
the global setting as set in Playback Options (for the first grace notes group) and
a customised manual duration/position of the grace notes, just dragging them like in a DAW (for the second grace notes group):
Here more informations, in the Manual:
Once you have visually set the desired positions, you can see the Playback Start Offset for every note and eventually copy the value to other notes (or just select the desired notes in all staves before you drag them):
I generally wrote out the “smear” in real notes and used two-against-three or four-against-three note tuplets in the different instruments to accentuate the “smear” effect.