We looked into using Vancouver as our departure point last year, but there were too many variables and associated expenses to make it worth the hassle. (How do you get there? If taking a car, you have to pay for parking and might hit horrible traffic at the border. If taking a train, you have to arrive the day before your flight. If you do that, you have to pay for lodging. And so on.)
However, if you could bookend a visit to Vancouver with your trip to Italy, that would be the way to go.
Definitely do open jaw. Lay out your itinerary in as much of a direct line as possible. Fly into one end of your itinerary and fly out of the other end.
Do use the matrix itasoftware link suggested above.
We put a premium on avoiding flights at ungodly hours of the morning or evening, so we're willing to pay more for that.