I highly doubt they would double - or even increase - the height of the crown. That just wouldn't make sense - architecturally or financially. But even with, say, a 6 story crown and 52 stories (averaging 13 ft. with a 18 ft. 1st floor), you're looking at something in the range of 750-775 ft., which will make a significant impact on the skyline. If they go for higher floor heights for LEED status, say 15 ft.), you gain another hundred feet. Either way, it's kind of a big deal.