Couple observations
Maggiolinas are like like alpine tents, the roof is low on purpose to help with passive heating. The roof and floor are insulated and you can get a winter hood that acts like a light windbreaker. I would highly recommend the ACS (anti-condensation) mat, works like a box spring and helps air out the mattress, give a nice little cush too. From what I hear from folks that go into really cold conditions is that you get about 20 degrees, so if it is 30 degrees outside it is roughly 50 degrees inside but it takes a while to warm up.
One fellow up in BC who does a lot of winter camping told me he carries a little 12 volt heated blanket inside the tent. When you are traveling have it plugged in so when you open the tent it is warm and dry inside.
Camping with a buddy in high elevation Mexico in the winter, he had a small Maggiolina Extreme and I had a small folding rooftent. I froze with two sleeping bags, he was warm with sheets and blankets.
I would probably steer you away from the newer Maggiolinas with the air springs toward one with the old style crank mechanisms. There was a cool old one called the Maggiolina Adventure, I don't know if they are still made. It was about four inches shorter and had a rack up on top so you could throw wet and dirty gear up there, stuff you didn't want in the truck. I used one about ten years ago and was really impressed. I woke up and it was really cold outside and had snowed, had no idea. But, I've never been in weather like you are planning for so take what I say in that context.
Rich