Been winter camping for over 40 years and used or seen many stoves in that time. Performance wise there's really little difference between heavy and light gauge steel. It's not like in a cabin where, after the first warm-up, each load is only used to raise the temperature 5-10 degrees. Every load in the stove is like the first warm-up. Regardless of the weight, that stove will return to ambient temperature within a few minutes once the fire goes out.
I find airtight stoves throw less heat, so they need to run wide open anyway, which defeats the purpose. A decent lightweight stove will throw more heat right away, and with a good damper and air intake can be throttled back for a longer burn. I run a 13"x13"x20" in my 8x12 wall tent and found it barely adequate for -40, it was maybe 50 degrees at the back wall, but with a full load of hardwood would burn for about 4-5 hours if I kept the damper about 1/4 open.
Whatever route you go, your sleep system should be good for at least the coldest you can reasonably expect just in case the stove goes out or you run out of wood in the night- I personally put in a load before going to bed and throttle the stove right back- I don't like the idea of a stove roaring away while I sleep!
