Macker, thank you very much for listening, your kind words as the precious hints, come d'abitudine.
The molto vibrato solution you propose is great: adding Solo Strings! They have great molto vibrato. Also, exploring progressive vibrato in DS could be useful. I've heard Guy Bacos using it in the most natural way.
I know this style is not my territory, so I had to keep some strong examples with me since the beginning. The original soundtrack; the Concerto di Venezia you cite (so beautiful!); Erik Snopko's demo for Elite Strings, to be sure of what a virtual instrument can do when used as it should; and a wonderful rendition made by one of my friends (Marcello's Theme).
So, yes, I will have to study the best models, and try to get some of their secrets. Che il viaggio abbia di nuovo inizio!
Paolo