That's cool that you have a font editor, Kevin. I understand they're expensive?
The text based hairpins were needed for NWC 1 but are native to the program in version 2. They work both visually and for playback. You can make them as short as 1 note or stretch them over several bars. They will look a little jagged in your edit window, but in print preview and in printing they'll be fine.
Take a look at this example:
!NoteWorthyComposerClip(2.0,Single)
|Clef|Type:Treble
|Key|Signature:F#
|TimeSig|Signature:4/4
|Dynamic|Style:ff|Pos:-11|Wide:Y|Justify:Right|Placement:AtNextNote
|Rest|Dur:8th
|Note|Dur:8th|Pos:b7
|Note|Dur:4th|Pos:6|Opts:Diminuendo
|Note|Dur:4th,Dotted|Pos:5|Opts:Diminuendo
|Note|Dur:8th|Pos:n4|Opts:Diminuendo
|Bar
|Note|Dur:4th|Pos:3|Opts:Diminuendo
|Note|Dur:Half|Pos:2|Opts:Diminuendo
|Rest|Dur:4th|Opts:Diminuendo
|Bar
|Rest|Dur:8th|Opts:Diminuendo
|Note|Dur:8th|Pos:5|Opts:Diminuendo
|Note|Dur:8th,Triplet=First|Pos:4|Opts:Stem=Down,Diminuendo,Beam=First
|Note|Dur:8th,Triplet|Pos:n4|Opts:Stem=Down,Diminuendo,Beam
|Note|Dur:8th,Triplet=End|Pos:3|Opts:Stem=Down,Diminuendo,Beam=End
|Note|Dur:4th,Dotted|Pos:#2|Opts:Diminuendo
|Note|Dur:8th|Pos:3|Opts:Diminuendo
|Bar
|Note|Dur:4th|Pos:5|Opts:Diminuendo
|Rest|Dur:4th
|Dynamic|Style:pp|Pos:-11|Wide:Y|Justify:Right|Placement:AtNextNote
|Rest|Dur:8th
|Note|Dur:8th|Pos:5
|Note|Dur:4th|Pos:5
|Bar|Style:Double
|Text|Text:"I"|Font:User3|Pos:8|Justify:Right|Visibility:TopStaff
|Note|Dur:4th,Dotted|Pos:5
|Note|Dur:8th|Pos:4^
|Note|Dur:4th,Dotted|Pos:4
!NoteWorthyComposerClip-End