I am thinking of buying a small rocket stove to have for emergencies (and hey to use to cook on in the summer outside). I have seen a number of them and I have a question on the feed tubes. Here it is..... Is a flat feed tube better than an angled one or vice versa, or is there no difference? My own inclination is that an angled feed would burn better as the wood would be angled so the fire could run "up" it like burning a match held at an angle will burn better than one held flat. Yes? No? Thank you!