Is Jotul C 550 Insert too big for my room/house?

I'm considering getting a Jotul C 550 wood insert. My house is fairly small (about 1700 sq ft, single story),
but the existing fireplace is big enough for the 550. And my wife wants the maximum glass
size we can get. The room that the fireplace is in is about 400 sq ft. Will the 550 provide too much
heat for the room? Could we burn smaller fires, and not run the blower (does burning smaller
fires cause the glass to soot up, or create more creosote)?

Also, my existing fireplace doesn't draft well at all. It's not blocked or anything - but we get smoke
into the house, even with seasoned wood, etc.. I think it's a combination of the existing fireplace size,
and the size of the flue and height on the chimney. Is it reasonable to assume that a wood insert would
work better? Thanks for any comments/advice.

The room with the fireplace is not closed off. It opens up to other rooms through 2 hallways, and 2 other doors.

The chimney is 18 feet high, from the floor of the fireplace. It goes through the middle of the house. It extends 3 ft. about the top ridge of the house.
And the flue is retangular (7" x 9" or 7" x 10", I forget which). There are no taller buildings or hills nearby. There are several taller trees surrounding the
house - a couple of large oaks and a couple of maples. But they are each 30' or so away from the house/chimney