-15f is -26 celsius, thats quite cold man, what sleep system did you use? After experiencing that how do you feel it would be at temps lower than that. I am planning for a trip to the arctic, either Norway or Sweden and a suitable tent and stove will be a priority. I have a freind who used to manufacture parachutes and parachute systems, if I supply a suitable material he can make me whatever tent I want.
Regards, mart.