If the underlying style has a Midi piano part, simply remove the RT from that part and save the style again. Use the RT picker, select the part, and press the None button. Then use the Save Style... button to save.

If you used a blank style initially, that is another story. You will need to find a BIAB style you like and work from there. There are plenty of style and one may have the instruments you want. If not, find a style and add the RTs you want, and save the style (preferably to a custom style).

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