Trying to get the rotations resulting from TwoBoneIKConstraint

I'm using a TwoBoneIKConstraint to position a rig and then using Forward Kinematics / direct rig transforms to control those same joints that the IK constraint positioned. I'd like to "bake" the transforms that are resulting from the IK constraint, that way I can lower the weight and gain control of those joints again. I've tried setting the rotations from when the IK weight is 1 to the transforms when the weight is 0 but that isn't it.

Is there any way to access that data? Or is there another approach? Currently, lowering the weight results in losing the IK solution before the joints are even acted on.