It could be like Pyrocat MC but with a different B part. Pyrogallol can work with a lower pH. I have used PMK with TEA as part B. It easily gives the 9.5 pH required. If you are accustomed to mixing your own Pyrocat, you could try substituting pyrogallol for catechol. The color of the stain will be different, as Sandy has previously noted. When you are playing around with these things, note that in many cases, ascorbic acid is more of a substitute for bisulfite than for any of the developing agents. It promotes the synergism between catechol and Phenidone or Metol or paraminophenol, whichever one you are using. As you see in the formula for Pyrocat MC, there are only 4 grams of ascorbic acid in a liter of stock solution.
Playing with these things reminds me of the admonition of a professional oboist. "You can't learn to play the oboe unless you play with it." He meant that if you don't learn what causes bad sounds (which are easy to make on the oboe) you won't know how to avoid them. That applies to most art forms. You explore the limits until you know where they are because the artist is one of the limits, and we're all different.
If you take a formula like Pyrocat MC and substitute the Pyrocatechin with Pyrogallol you effectively have an Ilford Pyro-Metol developer, the only real difference is the dilutions. A Phenidone/Pyrogallol version is shown in one of Ilfords Patents.
Ian. how effective is "effectively"? Is it one of those patents that seeks to cover all possible combinations of pyro and Metol? How about a Pyro-Metol-Ascorbic acid-TEA single solution concentrated staining developer?
I tried it out and the results resembled Pyrocat HD in terms of the lower base+fog (compared to PMK). The color of the stain was more of a brownie-green than a green-green, which leads me to believe that the alkali is either a carbonate or a blend of sodium metaborate and a carbonate of some sort. Bottom line is that the results were not noticeably different than I would get from the vastly cheaper Pyrocat HD, so I yawned and put the bottles toward the back of my shelf.