From the gouge...
What is the difference between Max Range Cruise [MRC] and Long Range Cruise [LRC]?
MRC:
The speed at which, for a given weight and altitude, the maximum fuel mileage is obtained.
It is difficult to establish and maintain stable cruise conditions at max range speeds.
1.32 Vimd constant speed with variable AoA [dependent on weight].
LRC:
Speed slightly faster than MRC at a constant AoA [slightly faster than Vimd]
As weight decreases, speed needs to decrease to maintain AoA
Reducing speed necessitates reducing thrust, though because best SFC for a given engine occurs at a particular design RPM, you must climb