I'm not a Mac user but I downloaded and opened your SGU file and the current Style in the downloaded SGU is a MultiStyle and it appears the Style is using the default soloists in the style.

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BIAB 2025:RB 2025, Latest builds: Dell Optiplex 7040 Desktop; Windows-10-64 bit, Intel Core i7-6700 3.4GHz CPU and 16 GB Ram Memory.