I vary just a bit from Rick's process, but not much. The idea is the same - you just gotta find out what works.
I go ahead and give it its' full temp first temper. It needs it anyway.
And I over bend almost as far the opposite side as it is off on the first side. I've never found going straight to be enough. Even when over bending, it sometimes requires a third temper at about 350 to really zero it in.
That said, I have done exactly as I just laid out, and put an over bend warp going to the other direction!
All of this is also dictated by the quality/condition of your blade when you heat treated and how successful you were in getting maximum martensite in the first place.
Geometry of the blade comes into play. Remember - lateral/side-to-side strength/flexibility of a blade is determined by its' geometry.
Steel type can matter, too.
Some steels lend themselves to being used as springs for a reason.
They just spring right back until you get a high enough temper, so when straightening, they require a bit more of a bend.
I just use a C-clamp and a flat piece of steel with a simple shim to create the over-bend.
Place the C-clamp on the apex of your problem.
You will need to add time to your tempering procedure as the steel bar/jig/whatever will also need to be brought up to temp. I normally add about 20-30 minutes time to the second cycle.
