Dear Miles,
Thank you for following the
thread and for your question. And thank you for posting those links early in this thread.
As for an ozan: We have one. The night picture of the tipi shows the light from inside only emitting from a band rather than throughout the whole cone. The bottom of the tipi is shaded due to the RMH bench that lines the inside, plus the liner that extends slightly higher than that. The upper part of the tipi is shaded from light due to our ozan.
Last year Tony and Emily clipped a thick piece of canvas up overhead, we guessing about 9' from the ground. We wanted a lower ozan, so we used a larger, but thinner piece of fabric for this. I am not sure how effective the ozan is for several reasons. The first is that our ozan is a life hack. We pinned our ozan fabric to a rope attached to the poles via binder clips. I think this method, although not entirely neat and tidy looking, is taught enough and holds well. Where it could use improvement is probably in the fabric type (something thicker, or just of well-known insulative qualities), as well as an extension to the liner. We currently have a 6' liner, and an ozan that sits a few feet higher than it, so we need to extend the liner up to meet the ozan. Last year Emily and Tony did this by using several blankets to bridge the gap, but Emily had suggested that we get a 9' liner in order to avoid using this hack-alternative. I imagine that a solid 9' liner would also be less drafty than a spread of several blankets.
Now, having mentioned all that, I will state my doubts about the effectiveness of an ozan in a tipi with an RMH. When fired, the RMH's barrel radiates a lot of heat, and yes, an ozan would be effective in trapping that heat, slowing its journey up and out of the tipi. However, besides the barrel, the bench also retains a lot of heat, and emits it very slowly. When it comes to heat retention, I would say that I rely not on the ozan to keep the heat during and long after the RMH has been fired, but the mass, the bench. The bench delivers heat conductively. You have to touch it to feel its heat. You have to sit on the bench, lie on the bed. The ozan, on the other hand, helps retain heat by keeping the atmospheric heat from rising, which is a process that will happen eventually anyways, and rather quickly compared to the rate that the bench loses its heat. When it comes to sleeping, we haven't fired the RMH at all through the night, so there's no radiant barrel heat, just conductive mass heat. And so, although the mass's heat does eventually radiate as it slowly cools, its not enough of a heat loss to want to trap that heat by ozan.
However, I state this "ozan heat trapping effectiveness vs mass heat retention" doubt only after having lived in the tipi for a month, with outside temperatures only reaching as low as about 5. Maybe as it gets colder we'll look to trap every morsel of heat that we can.
Thanks for sending your question. I'll keep a close eye on changes and observations in regards to the role of the ozan.