[pcr0]

In Hong Kong, most apartment buildings built in the last 15 years are about that height or taller. New commercial buildings are often double that.

Though your measure of effect on the surrounding community wouldn't really apply here as the buildings aren't that tall when compared to surrounding mountains.

[chordatum]

I agree. That particular horizon figure is the only one I know off the top of my head, due to reading up on naval ballistics. Hence the remark about sea level.

Anything else requires some napkin math about the circumfrence of the earth and radial offsets for non-sea-level terrain, combine with a bit of triangulation, to estimate skyline impact. Then, heaped on top is the effects of local topography contours and relative relationships with other human structures.