Nobody seems to want or be able to answer so I'll give you a partial answer.
I would assume that as the docks are a bit outside of St. P. that you would go straight to the ballet, they run several performances a day and are worth seeing. I don't think it will be necessary to change for the ballet as you might normally as tourists are not so culturally aware as ballet "goers". ( dreadful word) One tip is that if you would prefer a box just ask the usherette and slip her $5 and it is normally yours for the asking. Regards. .... Neil