Version 1.4.1 is here! It adds the ability to adjust the output volume of each track.
You can now modify the output volume (+pp+, +mf+, etc.) of each track in the ABC file. When a track is selected, there is a volume bar beneath the octave transpose.
While you're adjusting the volume, the display shows the volume of each note, instead of the pitch like it normally does.
If you adjust the volume past the minimum or maximum volume, the note will be drawn in red and the volume will be clipped to +pppp+ or +ffff+.
Visit the Maestro page to download the latest version.
This screenshot shows adjusting the volume of the Harp track: