Planning to be in Venice in mid September and want to go to La Fenice, probably Traviata

Websites seem to only have seating categories and want to get good seats. Are there any websites that allow choosing specific seats as in NY theaters?
In second category seats might be way on the side or more central, seems we might be unfortunate and get some at extreme side but still pay as if for better seats. In first category seats might be either in orchestra or balcony, I would prefer more central balcony if paying such large price
Thanks for help!!