Good morning, Nathan;
There are two ring flash units here; a Minolta 80PX and a Sunpak DX-12R. And, now that I think of it, I need to get both of them out together and look at them. There could be a much stronger family resemblance there than I originally thought.
The DX-12R is the one I have been using the most lately. It does have the adapter rings for 62, 67, and 72mm. If I cannot find the 49, 52, 55, 58, and 77mm adapter rings, I might buy some step-up rings and take them to a machinist to have them turned down to fit into the ring flash mount.
So far, the DX-12R has been working fine for me. And, my Sunpak 120J, 422D, and 544 have all been working fine. So have the Vivitar, Promaster, Minolta, Metz, and even the venerable Honeywell-Heiland 600C.
Of all of the electronic flash units I have (and there are a lot of them), the main problem has been my forgetting to take the batteries out when putting them away, and later learning that the old batteries have leaked and I need to clean the corrosion off the metal parts in the battery compartment. This is not a fault of the flash unit.