I know I had to take the same approach with Reaper calling on BBW using AutoHotkey scripts that I ran from a Lua script in Reaper to access Biab functions then I could write the data to clipboard to send to Biab and copy to send back to Reaper.

Code
reaper.ExecProcess([[cmd.exe /C " cd ]] .. [[C:\\Program Files\\AutoHotkey & AutoHotkey.exe]]..[[ "]]..script_path..[[ahk\scripts\play.ahk"]],0) 
reaper.CF_SetClipboard( start_measures ..",".. number_measures )
text_tempo = reaper.CF_GetClipboard()

that was all a lot of messing around so I just put it all in one script to read the current frozen SGU and transfer instantly.
Why have a hidden Biab running in the background when you can run the main Biab app and instantly transfer giving a lot more control ?
[Linked Image - Only viewable when logged in] But eventually I can't see any other way than a self-contained crossplatform JUCE plugin that does it all, and works the same instantly in all DAWs. It just takes way too many years getting there, I'm gettin' old frown

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