If you can help out and make some up in Biab and save as frozen SGU that users can try if they have Reaper, you can make more than 255 bars if need be by creating another frozen SGU for other sections
SGU can be imported using Working In Biab & Reaper Simultaneously and Instantly the section can be copied to a new project Tab and pasted one SGU after the other importing the chords and setting the region color of them, you can have multiple sections of the same chord, you can make up multiple 4-6 bar Endings using Holds
then use Live Arranger Using The BB Plugin in Reaper (you don't need the BB Plugin if you are using frozen SGU's)
See Video: Reaper-BBPluin-Song-Sections.mp4

You can enable mute buttons or drag the clip volume up/down when all selected
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