Hi Thierry, good you got to it! Be sure to burry it deep.
I am not quite sure what you mean with 6 or 8 shoots. Culd you put it in cm or inch?
Wery good idea on steel pipe. This is the only mistake l made, l put in a 5" wood stove enamel chimney pipe. Its put together in 1m sections. No good! Moisture creaps trugh the seams, dust, heat and soil pressure cripled it.
It is wery important to make the flue easyealy reachable for cleaning. It will collect tar when fired cold and later when heated up it will collect dust. Allso make a “lighting hach” to aid you at startup. Just light a bit of newspaper to create draft.
Ha, Don, not far from the truth. I fired it up before winter for a few days non stop, the sandstone cellar wall some 6 feet away from the burryed heater was warm.