HI! I bow before your infinite wisdom. I am purchasing a new furnace and was leaning heavily toward the Rheem modulator, but was told by the heating contractor that my 3.5 ton a/c unit will not be compatible with that model. He recommended the Rheem 90+ single stage. He said that the a/c was oversized for my house. He did not perform a manual J. This is only my second estimate and both contractors said " i see this kind of house all the time, a manual J is not necessary." ? can my 3.5 ton a/c work in happy unison with my future modulator, or should I look for something else.