Why not create a seperate new app focused specifically on simply editing in a user-friendly graphic way any of the up-to-eight chord progressions contained in a .clb or in a .cld file in the manner of arranger apps like BandInABox or iRealPro. ?
Such an app would for example let one create , quantise ( just at quarter-note resolution - ie single beats - no more needed imo for most stuff ) and edit chord progressions. Currently I often improvise a left hand chord progression and record it - but the timing - and occasional chord command is often mistakenly off - so an easy means of just quantising the chord sysex commands to the nearest quarter note or half-a-bar etc is fine.
I think you would find there is a new market of customers for you if you do this in Yamaha land! And willing to pay for it - specially if cross platform ( easy if you use a developer IDE/API/language like XOJO ).
And you could also consider just releasing this new functionality as a new app - and I suggest could charge a fair bit for it. As no-one including Yamaha is doing anything like this at the moment.
I would also suggest adding some features to support importing chord progressions from other common file formats - such as MusicXML and ABC Notation. Both BIAB and iReal Pro support exporting their "songs" ( progressions ) as MusicXML - and BandInABox also supports exporting in the ABC notation format as explained here: