To decide whether you can maneuver over or around...
Work out:
Range x 100
x tilt (in degrees) (-1.5 deg)
= height in feet above your level!
Has anyone actually used this to gauge cloud buildups?
It's all good, assuming that the radar will be able to "see" the moisture above freezing level, which usually is NOT case...
Personally, I wouldn't trust the radar to determine the tops above FL200 or so... There might be a buildup ahead of you giving a very weak, or no return at all if you point the antenna ahead.
My take on it is to use lower tilt angles to scan the lower parts of clouds and treat any radar echo as if it were at my altitude, unless I can positively determine visually that the tops are significantly below...