Intrigued by double-barrel side-car.....

So I'm intrigued by the photo below taken from this thread: https://permies.com/t/204583/rocket-mass-heater-tour-folks

Is the main Rocket Heater porting into a riser tube within the 2-barrel tower or just porting directly through the sidewall?  And if I'm conceptualizing this design correctly, at what height is the exhaust port positioned on the 2-barrel tower?  Is the latter just for heat dissipation with no appreciable internal mass?  Thanks!....

Hi John as this stove is newer and at the lab im sure someone will answer specifics. In the mean time here is the link to the full build which has extensive info. https://permies.com/t/193821/inch-batch-box-rocket-mass

The sidecar is just a bell, no riser internal--though I'm not sure if they put in any mass tower within. My gut says no as I think the triple barrel surface is maxing out the ISA of a 7" system. Hopefully someone will be along soon to confirm that.

UPDATE: Hey, just checked out the link I supplied and saw that a very nice video got posted last week discussing the build. Check it out, answers all your questions.

Much thanks, Daniel!