I have a Majestic 48" wood burning pre fab fireplace. The pipe that runs from the fireplace to the top of the house is I'm pretty sure 12". I measured it last night and its greater than 11" but laying on your back and trying to measure was a little tough for an old man. I'm wanting to get a Jotul F100 and sit on my hearth in front of the fireplace how would you guys recommend interfacing to the 12" pipe/chimney.