I'd like to reiterate Rick's often-stated request for incremental extra note spacing. It's needed for extended passages of crossed voices, such as the alto and soprano in the attached example of a choral piano reduction for rehearsal purposes. I don't know about the rest of you, but I think this looks really crappy. Even just a half-space option would be vastly better. Decimals would allow fine tuning. Please?
There is another use case where fractional extra note spacing would provide better appearance for layered staves. When whole notes are on adjacent staff positions, the "weak side" note is moved by more than one note width, so notes on a layered staff that have extra note spacing of 1 will not quite line up. See the following clip.
!NoteWorthyComposer(2.75)
|AddStaff|Name:"Staff"|Group:"Standard"
|StaffProperties|EndingBar:Section Close|Visible:Y|BoundaryTop:12|BoundaryBottom:12|Lines:5|WithNextStaff:Layer|Color:Default
|StaffProperties|Muted:N|Volume:127|StereoPan:64|Device:0|Channel:1
|StaffInstrument|Trans:0|DynVel:10,30,45,60,75,92,108,127
|Clef|Type:Treble
|TimeSig|Signature:4/4
|Chord|Dur:Whole|Pos:-3,-2
|AddStaff|Name:"Staff-1"|Group:"Standard"
|StaffProperties|EndingBar:Section Close|Visible:Y|BoundaryTop:10|BoundaryBottom:10|Lines:5|Color:Default
|StaffProperties|Muted:N|Volume:127|StereoPan:64|Device:0|Channel:2
|StaffInstrument|Trans:0|DynVel:10,30,45,60,75,92,108,127
|Clef|Type:Treble
|TimeSig|Signature:4/4
|Chord|Dur:Whole|Pos:-7,-5|Opts:XNoteSpace=1
!NoteWorthyComposer-End