No offence, but a 5 hr burn with 20" fir logs seems awfully short to me unless the stove is burning as hot as possible, which should not be required for a 700sq. ft space, should it? That type of wood stove performance to me is very poor and just would not work for our winters.
With my BlazeKing, I EASILY get 12 hours from burning 3 x 8+/-" splits about 16" in length on average. Also, there is NO WAY that I'd want to get up at 3 am to stoke a fire for a 700 sq. ft cabin, nor any house. My house is 1800 sq. ft., 3 levels and I've never gotten up in the middle of the night to attend the stove whether burning fir or pine or even cedar and I don't fill it to it's max either, but usually just 3 splits about 8" across and 16" long. Even on the coldest winter nights, around -25 F (-30 to -35 C), I've never had to get up to refill the stove, I'd just fill it more on the colder nights so as to burn a bit hotter, plus I'd use birch, which lasts.
Sorry but I wonder if there is something wrong with your stove's performance, or your house really is extremely drafty?