Having spent many many hours patrolling the oceans at max endurance speed I can assure you that Vmd is where it's at.
A good operational practice is to use Vmd +5 as this will negate the constant use of thrust to maintain speed as a reduction in speed will give a reduction in drag and therefore the aircraft will accelerate naturally back to the previous speed without the addition of thrust.
This of course neglects the TSFC which could have an effect of the speed if your engines are running in a poor speed band.
One solution would be to shut one or more down but I wouldn't recommend that in a civvy jet!