I've made a few of these. The oven is off-set from the flue so there's no interference with the draft when the oven damper is open. When clean there's a slight reduction in draft when the damper's shut, and all the flue gasses are going around the oven (behind the fish). It's very easy to get a 450 oven-just put some small wood in the stove and open it up. The current downside is cleaning-has to be done around once/week to keep the outer channel clear for even heat. By pulling the plugs and ramming a poker back and forth any junk can be worked to the bottom and down the chimney into the fire. Even with the outer passage plugged with soot/creosote the oven works well; it's just a little hotter on the chimney side.