Cool setup. Doubt even classics shops (ex. Mark Warman's) have a Sun distributor tester. All I have is that old Sears RPM/Dwell Monitor. I suspect what we see in the video with the tester running differs from real life, due to the video frame rate, giving dark flashes as if missed sparks. Your eye doesn't see that since it averages more over time.
My 1965 Newport had a CD box on the 383, with OE points distributor, when bought (Delta? forget). I don't know if it worked as it should. There was a push-switch to change from CD to just pass-thru points. Seemed less than robust since just a thin ribbon cable to the distributor terminals. Switched to a Crane Cams XR700 optical trigger pickup ~1996, and now an e-distributor triggering an 8-pin GM HEI module and their coil.