If there was a thank you button, i'd be pressing it until my mouse broke. You were able to hack the soundtest to prevent the music from stopping after a while?
No, I use my usual method of halting the main CPU, then sending sound commands to the sound CPU directly through the MAME debugger with a debug script. Generating the debug scripts for each song is done with a batch script. As a bonus feature, it means that the same code works on almost every game on the system.
It's somewhat similar to M1, but it's basically completely automatic and more accurate, since the original sound hardware is used (M1 simply swaps the music data usually into the Super System 22 sound driver, even for System 11/12 games that use different sound hardware with a slightly different sound driver and different clock frequencies).
I might make a tutorial for all this once the next version of the VGM mod is out.
Some tracks loop too soon (Bred from the Gap, Worth Dying For). just something to remember as this pack will eventually need to be relogged (like all other System 12 packs) due to bad clock & timing values.