The CFM and dispatch paperwork both plan on idle descents. So take that for what it's worth. Maybe try a 3* and 4* descent to a crossing restriction while following the carrot and see the difference in fuel burn. Make sure you take into account the extra time spent at altitude for the steeper descent to make it realistic. Personally, I usually use 4*. Maybe 3.8* with a huge tail wind or 4.2* with a headwind, but it doesn't seem to be uncomfortable. I think what the pax hate is the acceleration downwards when transitioning from cruise to the descent. Some people I fly with slap the TR's to idle and roll in to 4000f/min in one fell swoup. I usually put my hands up in the air and scream like I'm on a roller coaster. Makes it more fun.
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Hey, it's not lying if what I said would be true if the facts were different......
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