I wouldn't use fresh tomatoes in December. It is the wrong time of year for good, fresh tomatoes.
I use Cento brand San Marzano (DOP certified) canned tomatoes for my sauces, unless I can get fresh tomatoes from my sister's garden. There are other brands, but the DOP certification means they are real San Marzano tomatoes, which IMO are the best.
I love Pizza Margherita (not Margarita, the drink), but when I had it in Napoli, Italy, the birthplace of the pizza, they used sauce, not sliced tomatoes. Again, December is not the right time to use fresh tomatoes in North America.
It is just like fresh vs frozen fruits and vegetables... when they are in season, I always go for fresh, but when they are six months out of season, frozen often taste better, because they were picked at the right time.
You can get fresh herbs all year long, so definitely use those. Good fresh Mozzarella is also available year around, and that is my preference on pizza. Just make sure you drain it well, so it doesn't make your crust wet.
Good luck, and don't get too stressed out over a pizza.
CD