Automotive Air Conditioning Information Forum

Superheat is not used in MACV because the compressor does not spin at the constant speeds. The TXV's are different according to how much refrigerant is required to load each evaporator. Smaller capacity evaps call for less refrigerant than larger evaps but you will see less capacity in smaller evaps. Smaller loads require less capacity. TVX's have preset superheat. That is why it is important to weigh the charge into a system. You want to achieve a full column of refrigerant to feed the TXV. This is how I was taught a billion years ago.

Some of Your techanical comments are basically applicable to variable displacement compressor optimization and have little to do with fixed displacement comps or evaporator capacity.
Evaporator fin density is a function of evaporator air velocity, suck verses blow through evap, , heat transfer between design of primary and secondary surfaces, and water shedding characteristics of fin louver/shape design. Fins which drain water easily can be spaced closer together.
hotrodac