"Tee Emm wrote: It also says "maintain an increased minimum thrust setting"
The latter advice has me tossed. Request opinions (facts?) on this statement."
My recollection on how this was explained to me concerns the amount of air an engine can process at given thrust settings. This explanation was simplified so that I can understand it...others will be able to explain it better.
At high thrust settings, the engine can process a lot of air without inhibiting much or any from entering the intake. At low thrust settings (and higher speeds), some or a lot of air is forced to bypass the inlet because it is "full."
Now add in rainwater. At low thrust settings, you would want some or a lot of the rainwater to bypass the inlet, just like the excess air. But it does not behave like air (it can't make the turn like air can) and most of the rainwater will enter the engine.
At higher thrust settings, I picture the engine being better able to handle the increased air and the rainwater. At low thrust settings, I picture the engine as being closer to a possible flameout due to the rainwater entering the intake. The low thrust setting and high airspeed would represent the least favorable scenario, so as a technique (or procedure for some types) I prefer a higher thrust setting along with continuous ignition.