You got some balls, i was on the roof before, I am not afraid of heights and its a little scary because the roof is totally flat and seems like nothing is holding you back from blowing away. I assume your harness was on!!!
The floor to ceiling glass is amazing when the radiators in front of the windows are removed and the ceiling is pushed up to the height of the floor above.
-control your breathing and take the shot on an exhale
-pull your elbows into your torso and/or sit down if possible
-find something to steady the camera, your body, or both, against: a streetpole, a parked car, a building, the sidewalk.
Swampass2: I don't know if you're a pro photographer or not, but message me if you would be interested in allowing us to use your first image for the Hancock Tower's marketing materials.