OK, first bad news...
I thought about what I was seeing through the eyepiece, and realized that the focal plane of the system was barely outside the Hyperstar. So, I took some measurements and saw that the hyperstar was located too far away from the optical axis of the main mirror. Part of the problem is the thickness of the oak board I have it temporarily mounted on. I did get some 1/4 inch aluminum plate which I can use, but that will only make about 1/2-3/4 inches difference. I remounted the location of the hyperstar closer to the main mirror, and put the secondary on the centerline (gave me another 1/2 inch), but now the main mirror baffle sticks into the optical train from the secondary. I don't think there's much I'll be able to do about that at this point. The changes I made got me close to the 39.8mm backfocus specified on the Starizona web page.
So, I may try some imaging with the current setup, but don't hold out much hope for this configuration. I have figured out a simplified mount for the hyperstar in the usual front-tube position, so I think I may try that next. I just need to figure out how to make the part safely (one cut is kind of tricky). I also need to figure out how to mount the Canon EOS-M on the hyperstar, but that's mostly a case of measuring the thread pitch on the hyperstar (not a t-thread) and making a custom adapter of the correct length to get that 39.8mm distance to the focal plane.
Gonna go toss a coin about the next experiment,