Since manufacturers make incremental changes to their films, it is hard to make comparisons. Off hand I don't remember when Altman/Henn and Richard Henry made their tests. But my best results with Pan-X during the 1960's was with the Beutler formula. Truly spectacular resolution. Cross section photographs show that Beutler developer acts primarily on the surface of the emulsion thereby increasing resolution. I tried D-23 but the results were not as good. Never had the patience for D-25's long development times.