Hi Jeamsler,
I have done exactly what you are proposing, I have moved my BIAB SFZ files to a second drive.
I just moved the folder with the samples "/Library/Application Support/PG Music Inc/Band-in-a-Box Sounds/Programs".

Although an alias to the new "Programs" folder placed in "/Library/Application Support/PG Music Inc/Band-in-a-Box Sounds" might work, I used a symbolic link instead.

If you are not aware, a symbolic link is similar to an alias but more durable if things change with the path.

I used this free program to create symbolic links, it's easy, and it works really well (no connection to developer).
https://www.macupdate.com/app/mac/10433/symboliclinker

Hopefully this helps.

- Jay


MacPro 5,1/12 core@3.46GHz -- OS X 10.14.6 -- ATI 7970 -- 32 Gig RAM -- Crucial 500GB OS SSD -- Samsung EVO 1TB Audio/Sample SSD -- BIAB 2023 -- Logic Pro X -- Cubase Elements 11 -- Too many plugins