Luckily we didnt need chains, temps overnight were below zero, -3 was the lowest, but fortunatly warmed to above zero around 12, so by then, any ice on the roads had melted, except sluch in the carparks. after the big fall on Sat Night, the snow ploughs had cleared to roads by mid morning. the driveway from the carpark to the road was only about 200mtrs long, and driving on the snow on this part was no drama.
On the drive up, i filled with a tank of Alpine Diesel from Jindabyne, costs a little more, but its the only stuff they sell down there till winters end.
as for economy, 3 days driving around the alps, and return to Sydney, 450Km, and 4 days return to work, average was 5.3L/100km so no real noticeable difference with the Alpine Diesel.