Keeping the forge smoke down, can be done by switching from the usual bituminous smithing coal to anthracite coal, or metallurgical coke. A lot of smiths use coke, for forging, in the calgary area. (so ask them about the fine points). The suggested forge fuels require almost constant forced air. And the firebox, ideally, should be thicker walled than the standard ones.
Good luck,
Regards to all,
SLAG.