On a historical note, doesn't Chinese-Canadian and Chinese-American restaurant food go back at least as far as the construction of the railroads? I recall seeing some turn-of the century pictures of Chinese restaurants in Prairie towns. The railroads workers included cooks and effectively spread their influence across North America (I speculate that that may have been at least in part to get away from the conditions in the work camps). I'm not sure what this means for the home vs. restaurant N. American Chinese cooking, but I'm not sure that distinction is that important. Don't many regions with strong restaurant cultures have quite different cooking styles at home? I, too, think there are regional differences in Chinese restaurant food across the U.S. as well as with Canada although there are perhaps more overlaps. I haven't seen "Duck Sauce" in my western home town. I do miss the local Thai, Chinese, Mexican restaurant that had been run by a Thai woman who emigrated to El Salvador then to the U.S.