You would have been able to see the 4&5 WTC buildings. Well, at least what was left of 4WTC.
Here is an image looking down Cortlandt.
[qimg]http://i63.photobucket.com/albums/h131/triathlete247/WTC%20Attack/FEMAphoto_WTC-109.jpg[/qimg]
4WTC is seen on the left. The building with the flag is 1 Liberty Plaza.
Now, as you can see, from this vantage point, he is at least 15' above street level.
I base this on this photo
http://upload.wikimedia.org/wikipedia/commons/f/f5/Wtc-photo.jpg
and this basic map
http://www.prisonplanet.com/images/august2006/230806wtcplan.jpg
You can also use Ctrl +/- to zoom in abd out of the huge aerial photo, and see a large pile to the south (left) side of 4WTC.
And you couldn't see this above a 6' fence?