Using the Instant Trak Creator for Reaper you can create usertracks for Biab, they can be audio, video, multichannel, midi, as well as being able to have shots and holds, all formats use a csv. Reaper is compatible with many formats. It is just one script so it's self contained and all you need to install in Reaper (and SWS extensions if you haven't already).
Direct Download: ReaTrak-instant-trak-creator-gui.zip
In Reaper menu Options > Show REAPER resource path...
Open the Scripts folder and create a folder ReaTrak
Drag all the files and folders in ReaTrak-instant-trak-creator-gui.zip into the ReaTrak folder.
Go to menu Actions > Show Action List > New Action > Load ReaScript and go to the ReaTrak folder and open ReaTrak instant trak creator gui.lua
Run ReaTrak instant trak creator gui.lua

ReaTrak Biab SGU MGU.. to regions.zip will import SGU chords to regions, this way you can import Biab userstracks and add shots n holds to them. These can be adjusted as Pushes by moving back in the timeline and shortening, or just place a short Hold region 1/8 or 1/16 before.

To make sections with sustain instruments to have smooth transitions a decay can be added using -D -D1 for 1 bar -D2 for 2 bar decay.
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The pink countins can be intros or leadin notes
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Test tracks:
Vocal
Drums

The only thing with the test tracks the original ReaTrak had typos in the verse chorus Endings colors.
In the verse ending 254 should be 245
In the chorus ending 245 should be 254
After you unzip the tracks, in the View > Region Manager menu, right click to import the csv's and change the endings regions manually then export to save and overwrite.
If you place the edit cursor under the region then click Verse Ending or Chorus Ending button it will change the color automatically to the correct one to use the Instant Trak Creator.

GUI.colors["verse_ending"] = {151, 208, 245}
GUI.colors["chorus_ending"] = {158, 254, 182}

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The Drum sections work the same, just click the "Decay -D" button after you have "ReaTrak Section" (generated selected section (time selection) on selected track) this will extend the items by 1 or more bars to give natural decay without crossfade. With the brown Drum Riff sections this will give natural decay also so the last hits will decay into the next riff.
With Reaper you can have more than 255 bars so for a chorded usertrack you can put all the chords on one track when creating them, with key scale solo tracks have scale/Scale in the name, if it's a drum track have drum/Drum in the name, these will just match the color to color sections.
You can also add shots n holds to the same usertrack.
Save the regions as csv the same name as the midi usertrack.
Piano, Upright, Rhythm Pop 01 Ev 4-4 80bpm.csv
Piano, Upright, Rhythm Pop 01 Ev 4-4 80bpm.mid
or with key name
Piano, Upright, Solo Pop 01 Ev 4-4 80bpm Scale A# Major.csv
Piano, Upright, Solo Pop 01 Ev 4-4 80bpm Scale A# Major.mid

To import to Biab just select all items on the track, right click Glue Items then it can be dragged out of Reaper and dropped onto Biab to import.



Shots n Holds example:
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https://stash.reaper.fm/u/ReaTrak (Scripts for Biab Reaper)
Open SGU in Reaper Instantly