A good point, about snow load. Are you using 2X4s, for the rafters? 12' is a wide span. You say you only get 8" of snow, usually. Same where I live, but there have been times, when we got 30"s in an afternoon. With a 12' span, and it doesn't look like you have a lot of pitch to the roof, I think I would have used 2X6"s, at least..
