<< Even then I don't know how to add/remove bars for only a melody/single MIDI track. >>
I'm not sure what you mean but BIAB has the feature to import just the Melody track from a file.

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BIAB Ultra Pak+ 2024:RB 2024, Latest builds: Dell Optiplex 7040 Desktop; Windows-10-64 bit, Intel Core i7-6700 3.4GHz CPU and 16 GB Ram Memory.