I'm not sure why people think that smoke would come out the side, the heat will push the smoke upward and not squeeze it through a tiny crack since there is no back pressure.
So you got a fireplace that doesn't really admit Heat I just looked pretty? Isn't the reason we want to fireplaces for heat? Even if you're outside can't you design a fireplace system that curves so that you might have a seating area in front of it for warmth?
Want to make it bigger the height want to be 12" off slab then I want the fire block to be larger 40"high and 36" wide 26 deep finish Platform I want 84 long x 48wide x 16" tall then the box. If I can't back the boxer what is the largest I can get. And was t a light color if possible height to be 144" from floor to top of chimney let me please Thank you David Brunner