I recently purchased a Vigas lamda 40 used, I have always run a old Jensen wood boiler so gasification is new to me, my question is the stove pipe, the outlet on the stove is 7 inch inside dia. the bypass on the stove door is only 6 inch so my question is can I get away with running 6 inch double wall pipe up the side of my building as opposed to 8 inch, I am on a tight budget installing this unit and the 6 inch pipe is almost half the price as the 8. I am not worried about a little smoke coming out the door when it is opened seeing as though the boiler is in a detached garage, and always have the option of installing a elec draft inducer. I just don't want to effect the performance of the stove, any ideas!