What is the winning position in Monopoly Empire?
First off I don't see much of a difference between your 2 questions.  

The rules state:


  If you’re the first to hit the top, you win!


This means you have to fill the entire tower with billboards, including "spilling over". No, you do not have to fit the billboards in the tower exactly. Anything beyond the top point doesn't matter anymore since you've already won.