I'm not really into chemistry but this is what I have used successfully for many years... 1/2 to1/4th pt as to 1 pd and 1/10 gold chloride, 2 FeO I to 1 FeoII (from Bostick & Sullivan) diluted with distilled water 1 part to 6 of the emulsion combination. I generally mix enough for several prints measuring with pipettes in 0.1 ml's. I keep it in a covered shot glass and coat one paper at a time. Two 15watt bulbs illuminate the room plus very little ambient light. If additional contrast is needed I add hydrogen peroxide for that particular coating. In south Fl it is usually pretty humid although I work in air conditioning. When I was getting some voids in coating I pre-wet the paper with brushed on distilled water and let it dry but until it almost felt not quite dry dry. Ammonium citrate is my developer which I keep and add fresh as needed for volume. It has worked so I haven't messed with it.