I have a rear vented Hearthstone stove that has a very low hearth to flue center distance - about 21 inches. I would like to buy a Jotul stove that would require me to increase that distance to about 5 more inches. I have a Class A chimney that runs up 30' within an outside chase, which is 5 sections of 6' chimney pipe. Is there anyway I can change out one of the sections to allow me to raise the connector thimble by 6 inches or would I have to replace a 6' with a 5' and have the increase be 12 inches? That would be too much of a vertical offset for the stove.