Yes, besides the actuall tonnage rating of the coil and condenser, the system has to move an appropriate amount of air. Depending on your local climate, the amount of heat and the amount of cool needed are often quite different. Arizona and Montana might be two extremes of that situation. That is why modern furnaces and air handlers have multi speed motors. You might need a small amount of heat, and maybe a slower blower speed. And you might also need a much higher amount of cooling, and a higher blower speed.
Any given furnace or air handler will have a Maximum CFM air flow rating. Trane for sure makes for example 70,000 btu furnaces in many models, in terms of the max cfm and tonnage of cooling which they can support.
SO, this is still the big unknown in your equation, until someone who is really well versed in this field checks it out for you.
Before you go off half-cocked...a proper heat load calculation must be performed on YOUR place. Depending on the construction, insulation, window sizes, orientation, and placement, there is no valid one-size per square feet calculation that will do you justice. If the calculation determines the ideal size is inbetween available sizes, you always want to go to the lower sized unit, not the larger one. An a/c unit works best if it is running all the time. A big one will make the space cold but clammy, since it only runs a short time and can't dehumidify. Now, I suppose in the desert that has some merit, but not for longevity since things work better when they aren't turning on and off all the time.
Important note - I'm not a pro
Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013