Can anyone help me with details as to which evap coils to purchase. Two story home....no load calculation available. Original builder installed 2 ton condensers and 2 ton evap coils. 75,000 BTU furnaces. Upstairs has 200 more sq.ft. than downstairs. No total square footage available. Should I upsize the upstairs to 2.5 tons?? Purchasing two Lennox XC14 single stage condensers up to 16.20 SEER, and two 80% furnaces. I can't seem to find much information as to what evap coil I should purchase to get maximum efficiency....Can anyone help?? Thanks, Dillard.