Here is my understanding about the instrucions - it is my process to write things out which I am trying to comprehend.

Each of the six (6) BIAB Instrument tracks (Piano, Guitar, Bass, Strings, Melody. Soloist) can access\use (better word is share) 16 channels of data, But it is not 16x6 since only a total of 16 channels are available.

BIAB assigns a specific single channel to each of the six tracks (melody is channel 4, piano in channel 3, bass is channel 2...) this permits each channel to be assigned a specific GM patch for a specific sound.

John is suggesting I place in the melody track - multiple channels. The patch assignment is still limited to what is assigned to each of the 16 channels. So channel 2 on the Melody track (which contains the melody notes) is asigned a piano patch/sound, then if I also place the chords on the melody track, but on a different channel they will sound like what ever sound is assigned to that channel. For example, if the chords where placed on the melody track on channel 2, they would sound like a bass. Since channel 9 is not a preassigned BIAB channel I can use it and assign any patch I want, but since I am using the chords only to drive the VLT perhaps i don't even need to assing it a patch?

While each of the standard BIAB tracks are single channel (at least as I have ever understood), it appears that RB will allow me to create a multichannel track, combining melody and chords on two channels of a single track.

Does that sound right so far?? I need to move forward but want to be sure this is correct up to this point.

By the way , I am trying to use the Piano roll window in BIAB to understand all this.

BIAB – 2025, Reaper (current), i7-12700F Processor, 32GB DDR4-3200MHz RAM, 1TB WD Black NVMe SSD, 2TB WDC Blue SSD, 1TB WD Blue, 2 TB SK NVMe, 6 TB External, Motu Audio Express 6x6