Centaurus
I Know your background and acknowledge your wide experience. I would however suggest that your advice in this area is not appropriate to some more modern radar units.
The CAL (calibrated) gain setting yields the most accurate correlation
of color levels (black, green, yellow and red) with actual rainfall rates
and their corresponding thunderstorm threat levels.
CAL gain is the recommended gain position for normal operation.
Figure 4-38 shows a radar display with gain set to CAL.
The above exerpt is from the Collins WXR2100 manual.
I can't tell you how frustrated I get sitting next to guys who, lacking an understanding of advances in the radar world, apply procedures that are outdated and inappropriate to the equipment they are using, and end up diverting around returns that are either innocuous or below them.
Proffer advice by all means, but may I suggest you qualify it.
Maui