I would recommend that the elevation is displayed in one of two ways:
1. By having a number (DEGREES) displayed along the sunset and sunrise line, or at ANY time, as the time-slider is moved, or...
2. By having a little box with the "Elevation" displayed in it, near the origin point.
3. Having ALL the information displayed in a box: Date, Time, Location, Direction (Degrees) of the sun and moon and elevation for both. Negative values would be BELOW the horizon and positive values above, always seen as a positive value from the horizon (so going over 90 degrees would yield a number that decreases).
But - for now - while you think about it - ANYTHING would be better than nothing...
Most people who would use this kind of