[gjbingham]

Jim,
I'd give it time. I love the physics utilized in the the last two posts, but every oven is different, if not only for the reason that the archways and vents we build are not made from a cookie cutter.

Cool fires will put off more smoke and will not draw as well out the chimney. Deal with the smoke and the stain on your brick for the time being. Cover the brick with masking if its killing you to watch it get black. Once you get the dome to burn clear is when you will know if you need to work on your vent. If the oven is 800 degrees and your still getting smoke out the front, then you will probably want to do something.

I built 6 X10 inches for my opening on the inside of the arch. I widened it with a grinder to about 8 X15 with a slope towards the oven openng so that smoke spilling out of the oven would be given an immediate chance to rise and move up, rather than out.
Reality check: How's your wood? Really well cured? Wet wood produces much more smoke than seasoned.