How's the floor structure in the room? The most instrument friendly solution would be a "real" fireplace, one made of bricks and with ability to store heat.
That means the fire/smoke does not go into the chimney from the pit but circles up and around and under the pit before going to chimney, thus heating the stonemass. There must also be double steel plates to close the chimney after the fire's out. This way you only need to have a fire for about two hours (if it's a small fireplace) and the structure will stay warm for up to 24 hours or more (depending oin the structure and materials). That kind of fireplace doesn't get overly hot, but spreads the heat evenly and the temperature variation in the room is much, much smaller than with those metal things that get hot in two minutes and cold in 30 minutes.
I'm not sure if you know what I'm talking about, nor if such are available where you live. Some time ago I asked people here on the forum if any of them know what an actual fireplace, one meant for heating houses, is like. I was curious, cause I've never seen one in american movies, for example. IIRC nobody actually knew what I was talking about.
Light flashing!! You're in Michigan! There are lots of people from Nordic countries, Finland, Norway, Sweden, Denmark, aren't there? There must be sensible fireplaces as well!
But I do realise a stony solution may not be possible in this case. It needs a solid foundation as it weights hundreds of kilos and they're reasonably expensive too compared to mere stoves.