Vann; I think that your idea will not work very long before you cool the rocket burner down and choke off its supply of oxygen... by feeding cooling smoke into your
rmh fresh air intake. You must have sufficient oxygen & heat for a rocket to roar! Cut back on that and you will have incomplete combustion and before long you will fill your horizontal pipes with
ash, the rocket will quit drafting and your house will fill with smoke ! One idea for "seeing"the fire in a J tube rocket stove is to mount a circular store mirror over your
feed tube this will allow the fire to be seen from most anywhere in the room. The other way to "see" the fire is to build a "batch box" with a high heat glass top, however in your part of the world I think that would be too hot for comfort.