Originally Posted by
ChgoBob
Don't make two stops. You can buy the Florence-Venice tickets at the same time in Rome.
You can pick your seats using the tall machines. If you use an agent, ask for the seats that you want.
Every time I used an agent, we got seats facing each other, instead of next to each other. I don't know if that is the default, and the agents just accept it.
Also, when I stayed at the Sofitel Rome, they directed me to a travel agent just down the street that sold train tix commission free. Gave me exactly what I wanted including seat selection (I went for first class as it was going to be a long trip after a party week on the coast...)