Some of these are no longer relevant. If you notice a smoke not landing properly even though you're throwing it perfectly, look at Adren's new videos. They changed some of the skyboxes on mirage making some smokes easier and other smokes impossible from the same spots.
Ya I noticed this myself awhile back. I had watched some of adreN's videos on mirage smokes (not sure how old they were), but when I tried the smokes myself, some of them couldn't be set up like in his videos. For example, when smoking over the wall to A site, the palm trees you use to align your smoke now sway back and forth and they didn't do that when he made the videos so you can't line them up correctly any more. Not sure if adreN has made new videos since then.