I hope someone can advise me if this system sounds right. I have been quoted a ASX18036 with CAPF 4860 C6 and AMV8070 4B furnace(blower). My question is can the 4 ton furnace work at variable speeds with the 3 ton AC unit? No one has done a manual J and I don't know if the 4 ton furnace will be too big for my home. Thanks so much. I've enjoyed reading all the advise from the professionals.