The game already handles custom boss music, I think, via script attached either to the quest script (in the case of alduin battles) or in the case of scripts attached to aliases (like Miraak, Harkon and, I think, Karstaag).

DLC2MQ06, for example, stores this kind of data in the Miraak alias.

I'm trying to write a similar script for less "intensive" boss battles which works in a similar way: it assignes a custom music type for that enemy, and resets to the default music handling once the battle is over. can someone help?