Looks amazing, and I'm jealous. Question though...when you're emitting smoke, isn't that roof going to partially trap it and keep it down where you're working and breathing? I've considered something similar, but part of my plan would be extending the exhaust pipe through the roof or building in some other kind of ventilation.
I had my smoker under a big tree once and found even that prevented the smoke from dissipating when there wasn't a strong wind