Just by chance, today I came across a book - The Black and White Handbook by Hicks and Shultz - that discusses those 4 approaches for fine grain in reasonable detail. Well, now I understand 'physical development' and it is definitely not on my list of things to try!(posted 8544 days ago)I was to hasty in my opinions about Sod Sulphite. Indeed its not in rodinal, and going through the literature I see that smaller amounts are in acutance dev like fx-1 and fx-2. So, small quantities have only a minor effect on grain size and speed, and its effect is more as a preservative. Those percentages are useful numbers. Thanks Cesar.
My concern about sod sulphite was that as a solvent, while reducing grain size, will consequently reduce sharpness thru that very solvent action. I wonder if there are formulas for super fine grain that dont use a solvent and therefore dont reduce sharpness. But, its true, why fight the inherent characteristics of the film. If you want fine grain, use a slower film and a tripod.
George