There seem to be more Microdol-(X) substitutes out there than you can shake a stick at.

All approaches seem to take something like D23 (with more or less Metol) and to either add a restrainer (i.e. solvent action NaCl, KBr) or lower the pH (add bisulfite, boric acid or the alike) and thereby increase time of development and in turn solvent action of the sulfite or just do both. Besides the exact quantities used all aproaches seem to be pretty similar.

The formula quoted by Anchel and Troop may not be identical to Microdol-X but there has been information dripping out of Ilford indicating that the formula is darn close if not identical to Perceptol. In my view it can be seen as the the basic approach to the problem.

Stefan