Ted, I'm not sure if this is the direction you are are looking in, but I do soundtracks at home as a sideline to my retirement pension, and I find this simple system pretty handy for coming up with ideas...it's also available for iPhone and iPad.

https://autochords.com/

Ian
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Yamaha Tyros4, Yamaha MS-60S Powered Monitors(2), Yamaha CS-01, Yamaha TQ-5, Yamaha PSR-S775.