I run the mr buddy (the small one) in my two man works well, I havent had a problem with it. I still keep my sunflower for when its really cold and windy…
Mr Heater Portable Buddy, 4000 on low or 9000 on high, works great in a 1 man non-thermal for me. Use the Big Buddy for my 2 man. See Mr Heater has a new model Hunting Buddy at 6,000 and 12,000 BTU this year.
Operating time will vary depending on the heater setting and the supply cylinder size. Up to 3 to 6 hours on a 1 lb. cylinder. Up to 48 to 110 hours on a 20 lb. cylinder (based on “HI” and “LO” settings).
I use a Coleman pro cat in my insulated 1 man, I think it’s the older version of the black cat. Anyway, I like it a lot better than my portable buddy for a 1 man shack. plenty of heat and it stays lit in the wind or if I bump it, and it has a fan. Just a couple things that the portable buddy does not do.