JD,
Those formulas are for coloring copper based alloys only. (The title of the section is "Patina Formulas for Brass, Bronze and Copper".) If you are intending to use them on steel or iron, they won't give you the colors indicated and probably won't work at all. In fact, I don't think there are any formulas on that list for any iron based materials, so they would only be useful if you are talking about coloring brass rifle hardware.
CMAC - Nitric acid is sold in different concentrations but the very high concentrations are not available commercially. The strongest nitric acid you can usually get is ~68%. Above that (~ 85%), the acid is referred to a "fuming" and is a real pain to deal with. At 95%, we use it for rocket fuel as an oxidizer. IRFN and WFNA (Inhibited Red Fuming Nitric Acid and White Fuming Nitric Acid) are both such strong oxidizers that they are "hypergolic" with most organic materials, i.e. they spontaneously burst into flame without any other ignition source. The very concentrated nitric acid versions are heavily used in the manufacture of high explosives.
DC