I recently used the Casey Cold Blue on a couple of pieces of 5160 for accents on a knife. I got fair results.
Do some steels blue better than others because of the alloy mixture?
How should I get started with hot blueing?
Brownells has a book with about 75 ways for blueing or browning.It's not to costly. They also have lots of supplies. Maybe someone will chime in that has hands on advice.
Karl Anderson does a lot of blueing. Might want to PM him.