Not an HVAC tech, but where are your air returns located? I would agree that keeping the fan on will help mix the air in the house. Closing all the registers on the lower floor might stress the system, but you could close a few I’d wager and be safe.
I put coffee grounds where the water goes…
Not to mention Gimli sang a whole song in the great hall.
I only use a bus at the start for the mall and research. Once my first ore patches are dwindling I have transitioned to blocks by product as well as the mall. Ingredients in, products out. All by train.
I found a Lawn Boy in a barn a few years ago that I’m using. Two stroke from 1979. Infact those engines were also used as air cooled outboard boat motors.