What is the proper ratio between outside unit tonnage and the number of vents the unit can handle?

Answer 1

Too little information given to answer this question. The number of vents is determined by the duct sizing and the indoor unit fan capacity. There are several other factors that determine the number of vents that a system can handle.

Answer 2

There isn't a direct correlation between the tonnage of the outside unit and the number of vents it can handle. The number of vents a system can handle is more dependent on the size of the ductwork and the layout of the home. It's best to consult with a professional HVAC technician to determine the appropriate size unit for your specific needs.