Lots of great feedback, and I appreciate every one of the previous posts with insight or caution or encouragement. I won't reply and quote each person because I don't have the time right now.
The reason for doing this is not to install in a home, it is to see inside an active bell. As far as I know, all we have is temperature readings, and not a full picture, let alone a visual of a RMH in action. I also saw pictures and videos of people who put windows into their bell, and it is interesting, but again, not the full picture. If what it shows is "nothing" i.e. no smoke, that would be a HUGE thing to be able to show people! Obviously we can see it out the back end once it is running, and, as mentioned, it may be that glass keeps it from running efficiently enough to create the secondary burn, but how can we know without testing?
The concept of the glass not being insulative doesn't seem all that relevant, as the Steel Bell isn't insulative either. Of course the properties are different, and BS glass very well may malfunction as a bell, but again, I would not--nor should anyone--experiment with any part of an RMH inside a home.
The glass not being insulative would definitely affect the performance if put in as a riser or burn chamber, and I hadn't considered that, so I'll scrap that idea for the time being. I may come back to that someday for other reasons.
For a longer lasting "see the inner workings" experiment, I like my idea of a 10" system cut in half with glass on the viewing side, and the normal materials, albeit halved and oversized, on the other side. I got the idea from watching Steve Mould videos, where he does this kind of thing with plastic all the time. Here is a link to one particularly relevant to permaculture:
What I want and expect this (the BS Glass Bell experiment, specifically) to show is the EXACT moment when the smoke catches on fire and the stove starts to function at "phase 2" efficiency. Seeing that happen ... might help with progressing RMH technology in some way. It may not be all that relevant or worth the cost, but I had an idea and I wanted to put it in a few other brains, and it definitely got to some of the intended brains, so again, thank you for reading and commenting.
The side view experiment is probably a bit more obvious, but I would like a better way to "show" people what an RMH is and the current offerings of this site and youtube do not satisfy the person who wants to actually see what is going on inside and help them to understand the inner workings in a meaningful way. The drawings and diagrams and infographics are nice, but ultimately, are not something one can show a building inspector and expect them to understand.
I was at the RMH Jamboree in 2021(?) (I think the first one), and Paul wanted to experiment with his Juice Box Straw design. Things weren't working out like we expected after a week of experiments, and I think some "insight" into the inner workings of a RMH would have made the experimentation MUCH simpler and understandable. I don't know what happened with the Juice Box idea, it sounded good on paper, but we couldn't get the air flow right at the time. Being able to SEE the air flow inside likely could have given us enough information at the time to adjust appropriately and possibly give the idea some legs.