As an Eagle Scout, Brotherhood member of the Order of the Arrow, and wood badge trained scout leader, I've done a lot of tent camping over the years. My son is grown and gone now, I've been out of it for a while and I'm not familiar with the latest fabrics etc, but, I think, the most important thing about comfort is to get off the ground if at all possible. I would recommend a good cot.
One of the problems with tents, is a tent sweats, or tend to collect moisture, especially on a cold night, with warm breath and the flaps down. Moisture will collect in the low points, i.e usually on the ground and where you will likely wind up when you toss and turn when sleeping in a large tent on the ground. The ground cloth and "fly" is a great idea and will help quite a bit with moisture. If your off the ground you will stay much drier and much more comfortable. Remember the scene on Jerimiha Johnson where they bury hot coals and sleep on them? You will stay much warmer off the ground.
I've gotten old and soft, and usually take a kerosene heater with me, when I go, but I leave the flaps open in my 12 X 12 dome tent. In areas that have electric hook ups, an electric heater is a better choice as you don't have to worry about the Carbon Monoxide.
For backpacking, the smaller the tent the better, light weight, and body heat keeps a smaller tent warmer.
I love to camp and have camped all my life. My wife isn't as keen on it as she used to be, and her idea of roughing it is a holiday inn without carpet on the floor!
