I think the 30cm rule is based upon when you open the door to replenish the firewood, you have the potential for embers to escape.
I also seem to remember from the Navitron forum that two 45degree bends, with one as soon as possible out the back of the Hobbit SE, gives a better draw than one, more distant 90 degree bend.
Re: the bend(s), I may be limited to how far out the stove can go and what fittings are available but I will ask the dude who comes out to recce the install.
I think the 30cm rule is based upon when you open the door to replenish the firewood, you have the potential for embers to escape.
I also seem to remember from the Navitron forum that two 45degree bends, with one as soon as possible out the back of the Hobbit SE, gives a better draw than one, more distant 90 degree bend.