Pose Library dial wheel

Is there a way to set the influence of a certain pose in the pose library?
Like a dial wheel to set the amount of the pose?

For example, I have a pose for closed eyes. This pose only affects the eye bones.
But it would be nice to have the possibility to set steps between full open and full closed eyes.
I know I could do this in the time line, but what if I just want to close the eyes just halfway.