Heisler mentions that he spent several evenings on that roof trying out different cameras with different lenses.
Neither the 24mm Canon lens nor the 4x5 Camera could compete with the 8x10, even though he wanted to avoid bringing a large camera.
The focus is very selective because of the large format. Keep that in mind when you tie your expectations to the look of that image while shooting with your 35mm camera.
Heisler further explains that he "turned the knob" and the empire state appeared sharp and clear.
You could do the math and calculate the angles (how far to turn the knob), but simply trying until it works seems to be appropriate, too. After all that's what Gregory did with a deadline that I assume to be a tiny bit more deadly than yours.
With the math out of the way, Scheimpflug simply says that the plane of focus is not parallel to your film.
To set it, turn the knob(s).