Thanks, ccrunner. You're more organized than I am. I had to go look for my video.
However, I also found this one, which may be helpful.
https://www.youtube.com/watch?v=7Q7yFT_ehVUThumper, unfortunately, I have very little in calculations. My whole reverse was somewhat experimental, as I had to wait for the final test to see if it was correct. The two criteria that I had to consider, were the gear size and the starter motor bendix. I wanted as small a gear as possible, to reduce rotational mass, and to fit it into the engine bay. Once I found the gear, I looked for the most powerful starter motor, that had a bendix that would match the gear. As it turned out, a Skidoo starter motor has the nearly same bendix dimensions as the SBC (I think the difference was around 0.030" in diameter.) Those two factors made my decision. As to the RPM, I honestly don't know. I think in your case, you will need to use a reduction gear, because you are not going through a differential. I have seen some units like that on some UK suppliers websites for racing applications.
As to using the reverse, it is an acquired taste. Because there is no clutch, backing into a parking spot, wouldn't be my first choice. I see it as an emergency backup, when I'm strapped in, and need to do it fairly quickly. Otherwise, it is a lot easier to just push. And having a full cage, makes that so much easier.