And at high cruise altitudes (27,000 to 37000?) the manufacturer's hand book for Collins WXR-700X radar recommends adjusting the gain control to full max gain for scanning ahead. This gives a much more powerful radar beam to that in auto. Low reflectivity targets such as Cb tops which consist of ice crystals may not show up in auto but in max gain will then be displayed as a tiny return - enough to warn you of a Cb top ahead. Then switch back to auto gain to evaluate the solid storm cloud below that is causing the Cb top. Repeat as required. Have used this technique over the Pacific regions for years and it certainly works, much to my relief at night.