The most "efficient" fill level for a ball mill is to load material equal to 25% of the total volume of the mill. A 40% batch will take twice as long to mill as does the 25% batch. But, depending on your cycle time and unit operations, it may actually be more economical to operate with the "wrong" batch size.
Blending equipment, if operated for too long, can actually "de-mix" the materials that you had blended.
When sizing and specifying the correct vacuum and solvent recovery systems for your vacuum drying equipment, components must be sized for the peak vapor load, not for the average or total moisture to be removed.