I'm an happy and satisfied user of Pyrocat MC and this suggestion to make a sort of "Pyrogallol MC" is very interesting.

If I understand well you have to mix, for the Pyrogallol formula, the same amount of catechol + 2/3 of the weight for Pyrogallol formula.

At the end for one liter of stock solution, as the original formula for Pyrocat MC called for 100 grams of Catechol, it will be 150 grams of pyrogallol to mix Pyrogallol MC.

Am I right Pat?