I had a North Face Mountain tent. I would pitch out the rain fly much wider so it didn't go to the ground. A Coleman 2 burner lantern on low was set inside the fly but outside the tent. Not sure I was ever out in -30 but -20 for sure not counting wind chill.
In the Army I did German winters in a GP small or the even smaller Hex tents. Diesel canon ball stove just like on MASH. A liner for the tents makes them much nicer to winter in.
Pick your spot to set up on. Frozen ground can turn to mud inside the warm tent.
