This is a great question, and I hope you start a saga. I use video chat (Google Hangout) and it has worked great for over two years.
HBO Ars Magica, my current Saga, began with the idea of beginning with PCs entering their apprenticeship in the first session, and then playing 1 year every episode until the end of apprenticeship, whereupon it would slow down. I started thinking "Where would it be most likely for a large number of apprentices to all be trained together at the same time," and that led me to the Greater Alps and the Alpine Apprentices idea, a sort of loose "magical school," but with the PCs living at different covenants and coming together for approximately half the year to study. The Hibernia book was in the works at the time, so I suspected the group would eventually go there, which led to a couple of PCs being Irish. So, in summary, I began them all as children and we played through the years 1205-1220, which happened to include the Children's Crusade.
Often my Sagas in the past have begun with a covenant concept. For example, vrylakos ran a Saga in Spain, and I convinced him to do a winery, which I thought would be a fun income source. A Saga I started in Provençal used the ruins of Glanis (which were later detailed in the Provençal book). I once started a Saga by telling the players their PCs were all former apprentices to magi who had all dwelt at the same covenant -- masters who were now all mysteriously dead. The masters had secretly been responsible for both creating/summoning and then later binding a massive threat to the Order, but had died keeping it bound. The PCs knew nothing of this, but when they returned to their old covenant to investigate the death of their masters, they learned it all. "Big Idea" covenants, like "a magical school," or "a Hermetic version of the Arthurian Round Table," are great hooks that help the players navigate Ars's endless choices; giving the players something to focus on can make character creation easier, not harder.
I have a Tribunal Survey which I have used for my players, describing the various Tribunals and polling them on what they would prefer. Interestingly, the Theban Tribunal was the runaway winner. Players cited the cooperation that takes place there, the mythological setting, and the high magic. In other words, they'd rather be in conflict with Crusaders, Venetians, Monsters, and Pagan Gods than each other.
Now that Through the Aegis is out, were I looking to start a new Saga, I would be very tempted to just throw down one of its covenants -- probably the seagoing one, the Hibernian one, or the Second Spring one -- and take off running.