Hi folks,,i recently purchased a new Napoleon 1400 banf wood stove,, I'm replacing an old newmac..my question is.. The new stove has a top flu which is 6in. The double wall insulated going through the cathedral ceiling is 8 in. There are no elbows.. Will the stove draw ok if i use 6in single wall stove pipe from the top of the stove, then joined to 8 in. Double wall insulated that goes through the roof.... Thanks in advance for your help