Want to make a hack to play FE8 and FE6's legendary weapon themes (Blessings of the Eight Generals + Sacred Strength) whenever a legendary weapon is used, like with Hector, Eliwood, Athos, Lyn, Eirika and Ephraim. How do I do it?

Questions
1

Title says all. Making a slightly edited personalized hack for FE8, so it’d really help.

2

Follow-up. Also, I’ve tried using the Unique Battle Music Per Unit hack, but I don’t know what I’m doing wrong, except that it always plays the map music whenever I’m not using the Sacred Weapons (for FE8). Any advice?