I saw a good, in depth tutorial on heat treating on one of the badesmithing forums, some time ago. A copy of the Machinery handbook will have heat treating information, or you might check some of the blacksmith sites too.
Like Rich said, you can do as much damage, as good, with bending a cock. IMHO, the flint should be about 60 degrees to the face of the frizzen as it makes contact, assuming that the flint is the correct length for that lock. Remove the mainspring to check the angle, BTW.
I like to use a 1/4 thick steel bar clamped in the jaws, as a handle, to bend the cock.
If you bend it too far, then heat it and bend it back. It has been recommended to use a steel protractor clamped in the vise to judge how far you are bending, but it isn't really necessary. This is one of those bend and try experiences, so go slow and try it as you go. Be careful that the bend isn't so extreme that the flint bashes into the pan, when full down.
An easy way to check if a cock with a longer throw will improve sparking is to add shims between the bottom jaw and the flint. Adding the shims is not a permanent fix, it's just a way to experiment with length of throw and the angle of attack.
God bless