Stngllhm wrote:I do still need to add a couple of booster fans to the 8 inch ducts because the blowers on the stove are alittle lacking
Before adding any booster fans I strongly suggest that you get a cold air return in place. I have this same furnace in my basement. I'm heating 2500 square feet which includes two levels (3 if you include the basement) and an attached two and a half car garage thats been converted into a living room.
Whats happening is you are pressurizing the house and the blowers are fighting against positive pressure in the house. Not only that but you are probably heating cold air which requires a huge amount more energy to heat than air from a cold air return that is already 65 degrees. Those blowers should be more than plenty for a double wide if you get a cold air return in place. I built a box around the blowers with tin and ran a 24x8 inch square duct to it.
Just for demonstration, imagine your furnace adds 50 degrees to the air passing thru it.
45 degree air (from the room its in) + 50 that the furnace adds = 95 degree air getting back to the house.
Now lets add the cold air return from the house
65 degree air (returned from the house) + 50 that the furnace adds = 115 degree air getting back to the house.