Barrelbrowner;
Many of the same formulas can be used for either browning or blacking by the simple act of boiling after rusting or not. The boiling actually helps to loosen the non-adhereing rust so carding is actually easier in the blacking process. You might just first try your favorite formula before getting another, may find no need to acquire an extra.

Miller/TN
I Didn't Say Everything I Said, Yogi Berra