I'm in the same boat, but we got a foot of snow here. I've only driven FWD cars in the winter so I was not, and still am not use to what an AWD drive car does. I suggest waiting until there is enough snow on the ground so you can't see any dry spots, go to a parking lot (that has no cars) late at night, and mess around. Lose control, try and get it back, just see what the car does when you do certain things.
But your tire problem, Matrix
, is a bigger concern.
The difference in wear will take a toll on your AWD system, and not only that, but as your fronts are brand new, you'll want to remember that they're still scrubbing through their mold-release compound, and will not have best-pressure.
In addition to the above "basic lesson" that Kyle
suggested, I'd also recommend that you experiment with tire pressures (including the front-to-rear bias) a bit.
Our Subarus may be AWD - but a highly-regarded AutoX and track-racer once said, wisely, "remember that AWD is 'half RWD,'" that tail can and will come around to bite you, particularly under such conditions, particularly if you've over-driven the car's mechanical limitations.
Physics is physics, and our vehicles are bound by those undeniable laws.
Yes, getting better tires can help you either enlarge your safety envelope or help you push performance to that edge, but you'll still need to know and intimately understand the basics. Otherwise, you're simply setting yourself up for a failure scenario at even higher speeds, with even more potential damage and harm.