I have good experience with printing delicate highlights using a modified version of the Bostick&Sullivan formula. B&S formula contains oxalic acid (for better iron reduction), and ammonium dichromate for preventing the fog. I am using ratios as %25A and %12B. I have added 1gr of oxalic acid into A, 0,2gr ammonium dichromate to part B. This formula performs especially well with unbuffered papers (or de-alkalised papers with sulfamic acid). If used with buffered papers the effect of OA is somewhat reduced but the papers still retains more blue during wet treatment. It won't compare to the ware's modern formula, but it performs very good imo.