The ones tonight are lit after shkia and the ones tomorrow night are light before shkia. I heard that in Meron, tonight it’s the Bianer (Boyan to some) chassidim that have the biggest fire. Tomorrow it’s Toldos Aaron or Toldos Avrohom Yitzchok. The one tomorrow is lit right before shkia and they probably dance on for hours.
Shmoel: It’s quite long. But basically he says that Minhagei S’fira are unique and that you can change your Minhag from year to year to attend weddings.
R’ Schachter says that other Poskim point out that the Minhag is just against getting married. But you can attend a wedding no matter which half it’s in, so long as the person getting married isn’t violating his own Minhag. This seems to be the Minhag for most people.
Shmoel: You’re there to be M’sameach the Chassan V’kallah, which is a Mitzvah D’Oraisa. The music being there is part of that. The Minhag not to listen to music can’t trump that. (Also it’s a Seudas Mitzvah, which many say you can have music at during S’firah.)