I have recently acquired a Petit Godin 3726 (small oval). The manufacturer' tag on the back states that the stove is rated as "au charbon" (for coal). It is in nice shape, but after I got it home I noticed that the exhaust box is sized for a 4" flue. Now, I love the appearance of the stove. But burning coal is a bit of a problem for me. I was planning on obtaining a 4"-5" adapter, running 5" flue about 7' up to the ceiling, and then going to 6" for the last 8'-10'. Will this work for wood, or will it just turn into a smoking dragon, and fill the room with smoke? Any suggestions?