When I get some more p-aminophenol I shall see what the volume is without adding any more water. It may be that the volume of solids added to the 763 or so liters comes out to be about 1000 liters. It is difficult to tell because some solids seem to fit between water molecules with practically no change in volume. It is true that the conversion to sodium makes it tricky, and perhaps an excercise in futility. Would converting to moles of the potassium salts/ gram of solution before attempting the conversion help?
My opinion is that the sulfite content is not critical but should probably be sufficient to make the monosulfonate from the available aminophenol; that the developing agent ends up being the sodium or potassium aminophenolate, and that the presence of some precipitated aminophenol, at least initially, is important. The ratio of hydroxide to aminophenol seems to be such as to provide more aminophenol than can be converted to the phenolate by the amount of hydroxide provided. Anyway, it's fun to think about and play with.