Any professional musician will suggest pieces that are suitable for your ceremony. For example, you need something sedate for the entrance, nothing that's going to make you or your bridal party walk in too fast. Canon in D, Clair de Lune, or Trumpet Voluntary all work well. The signing of the register needs at least two pieces. Flower Duet and Le Onde are lovely and are certainly long enough. Then, the exit piece. It's imperative that this is upbeat, as people will be clapping and there will be lots of noise, so a fast tempo is a must. Consider Arrival of the Queen of Sheba, Trumpet Tune or First Arabesque by Debussy for this. Personally, I always suggest an online meeting before the big day to go through options, then we can take it from there, as there are always plenty more suggestions waiting to be heard! Remember, many film scores use classical music too, so this is a fantastic genre crossover to pick from.