While in Venice we plan to eat dinner at Osteria Naranzaria on a Thursday night around 1930. Do we need to make reservations and if not how long is the wait to be seated?
When you arrive at your hotel you can ask them to make reservations for you. There is no disadvantage in making reservations, even if it is not mandatory. The hotel or the restaurant may possibly tell you that 7:30 p.m. is a bit early for dinner in Venice and it's possible they may suggest that you make them for 8 p.m. instead.