Ducting Systems and Air Ventilation - Return Air

I heard that you should install a return air at least the same size as supply, for all rooms except bath and kitchen. Is this true? Also, I am using the space between my floor joists for my return duct, my question is -Does it matter how far away you go with return air duct? I am thinking of using space of my floor joists to get 28' to other side of house and then taking off from that and going through the dead space in my attic trusses to each return grill in living room, which would be around 55' from furnace to furthest grill. How do I size the return I need for each room?

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