I ordered an Up and Out Kit, included is stove 3" stove adapter, 3 to 4" adapter, 4" Tee.. On top of the tee fits an adapter for OAK, its 6.5" dia. Spec sheet gives dimensions but not enough. Any one know if I have enough clearance behind the hopper or do I need a short extension to the tee from the stove? There is 4" from hopper back to vent outlet.