You can try a midi style to construct the song quickly or to just send a midi track/s.
This will be very quick when you make a chord change and generate,
BUT when you generate select All Tracks (MIDI Only) so it's not taking ages to generate the rendered midi to wav on the other side of the Plugin.
You just set up some midi sends from the Plugin track to an instrument on each track for each midi channel.
The Plugin also needs the option to generate the RealCharts only (Instrument and Drum) this way you can send them to the instrument tracks (if they can get BB4 to do this quicker than generating the audio tracks as well).
If you look in the Win Plugin forum you will see more tutorials.

And here are the track channels thanks to MusicStudent
Track Channel
Bass 2
Piano 3
Melody 4
Thru 5
Guitar 6
Strings 7
Soloist 8
Drums 10

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Another way if you can't create midi sends is ElementVST/VST3/AU/AAX you simply load the Element vst3i or vst3fx
click view top right
now simply drag the Band-in-a-Box DAW VST3 Plugin.vst3 into it and the other instruments you need
connect them up
click MIDI in the list on the left and set channel from Omni to the instrument channel of the selected VST
*Make sure you have EXT on up in the top left so it receives sync.
Save that Element setup then just simply load it each session.
You can add whatever you need in Element like a midi transpose to transpose the midi signal up or down an octave.