I am going to hang a wallpaper with a very dark green (almost black) background. The personnel at the home improvement store said that primer/size could not be tinted dark enough and that I should use latex satin tinted to the background color. How long should I allow the paint to cure on the wall before I start hanging the wallpaper?

I recently purchased a home whose bathroom was in the middle of being redecorated. Short of it all is that the original builder (DIY) did not prime the drywall before applying the wallpaper and then somewhere down the road a different owner applied a new layer of wallpaper over the old. When I bought the home the owners were in the middle of removing all of the wallpaper. I wish to paint as I do not have a bathroom vent, but do have a window. The wallpaper will not come off completely in some areas, so the walls are slightly "rough" from the paper. Also have inadvertently removed some of the drywall paper. Any recommendations on how to smooth the walls in preparation for painting? Thank you!