Traffic decides more about a Los Angeles wedding than the venue does. Guests coming from three directions on a Friday afternoon will not arrive together, and the ones who left on time will be the last to park. Build honest padding into the start. Printing a four o'clock ceremony and beginning at four twenty is normal here, and the couples who plan for it are the ones who are not stressed at the top of the aisle.
Downtown and rooftop venues run on hard noise curfews. Amplified sound often has to stop at ten, sometimes earlier, and the buildings around a rooftop hold neighbours who will call. That works backwards through the whole night: the ceremony start, the length of dinner, the last song. We keep the ceremony tight so nothing after it is squeezed.
The late afternoon light is the reason people marry in this city. From about an hour before sunset the light comes in low and warm off the west, and it stays usable longer than it does at the coast because of the haze. Photographers will ask for the ceremony to land in that window. If you can give it to them, do.
Parking counts as part of the schedule and almost nobody treats it that way. Valet at a hillside venue, a downtown structure that closes a level, a street with permit only signs after six. Tell your guests where to leave the car in the same sentence you tell them the time. Rehearsals are worth doing on the actual site if the aisle involves stairs, which in this city it often does.