I don't know if it helps or not, but I was stubbornly sticking my guns about insulating my coop as well. I live in Northern Wyoming in the Big Horn Basin, a basin formed by three surrounding mountain ranges. It gets flat out cold here - some mornings I have to chip the neighbor's dog off my tire before I can go to the store.
JackE and I had a lively discussion about this, and I'm afraid I even got a bit rude about it. Well, as it turns out he made a lot of sense. My coop is not insulated. As he said, if my coop was heated the way a house is, then insulation makes sense to keep the heat in. But it isn't a heated structure. So when the moisture of the chicken's breath plus the moisture from their droppings and waterers is contained within insulated walls it's going to build up. A moist, cold environment is much harder on the chickens than a drier cold one. I have tons of ventilation in my coop to allow that buildup of moisture and ammonia escape and I can shut down the ventilation on the side where the winter winds whip the snow to cut direct drafts on my chickens. Watch wild birds outside during winter. They fluff themselves to trap the layer of body heat. Our chickens, for all of their quirks and differences, are still birds. I chose birds based on their winter hardiness in the first place, so it seems kinda silly not to let them do what they can do naturally. You can also add things to their diets in winter to help them produce heat for themselves...black oil sunflower seeds, etc.
Now, that said, there are as many opinions out here as there are chicken owners! If there was only one right way to do everything, then this entire web site could be read in half an hour. So keep doing exactly what you are doing....research, ask questions, and then make your final decision based on what you think is best for your situation. Then, when someone else asks the same questions later on, you can share what you did and how it worked or didn't work for you. Good luck, and share some pictures of your coop when it's all done! I don't know about everyone else, but I like to look at other designs and how they are implemented.