Makers of canvas wall tents, such as
Davis, usually include a stove jack made of steel that is a simple square sheet of metal with a circular hole cut in the middle. You could probably come up with something else, but that seems simple and effective.
Reliable tent uses a flexible silicone-coated fiberglass--that would probably be an advantage in terms of weight, but I'm not sure if it has any other benefits; maybe it doesn't disperse heat like the steel does and so provides additional protection. I would think it would be more expensive as well, but I notice they can be purchased separately from the Reliable website for $24-28. (Blogger compliance note: I don't have any relationship with these companies or personal knowledge of their products; I've just been researching wall tents since I couldn't afford a yurt!)
You could also check with these tent makers to find out what their experience is with customers' tents catching fire. I notice that all of them have warnings about the proper use of tent stoves and the fact that flame-retardant canvas is not fire-proof, just fire-resistant, and will still get holes in it from flying sparks and will still catch fire if any of the canvas is actually touching the stove or chimney. Those warnings are probably legally important as well as helpful.
I don't have a drill press and I don't have more than average experience with hand tools, so I'd likely be going for the full kit when it becomes available in California--and provided I have the money for it then. But it's exciting to see a new yurt-maker that's much closer to my price range!