I've stated before that stability in alkali goes up in the series Phenidone, Dimezone, and Dimezone S. The last word is that Dimezone S was the preferred agent and all new Kodak formulas would have used it. All Kodak instant films used it. Dimezone S is about the same in activity as the others. It appears to be less active, but that is partly due to the molecular weight compared to Phenidone.
I think that some scanned examples of films produced by this developer compared to Xtol would be useful.
Thanks for the comparison scans that Photo Engineer requested!