I was being very casual about swapping out the terms mass and weight, you'll notice I edited in a brief statement about this in the OP. The reason I haven't overhauled it is that so many members of this website haven't taken a chemistry class yet, they assume mass = size. Distance from the tower is of no great importance in my assumptions because I give an estimate on the height of the buildings in the Hub. They could be taller, they could be shorter, it's all approximation. If you have your own approximations of the heights of the skyscrapers I would love to see them.