I do get smoke shadows on snow... I think. Will doublecheck...
As for setting visibilitydistance lower, it does prevent the massive drops (at 3 FPS dropped from 60 to 20, or 16, and at 2 from 60 to 50/48 or so) when looking at certain parts of the city.
All buildings popup much later though, so the initial results are very good, I'm still trying to find out what the price to pay is, visibility wise I mean... it's difficult to determine whether it shows less objects now, as in, you do not see those...