Wish: Ability to enter a numerical value for the Dolly zoom

i thought i could offer a nice workarround - but it does not function:
show the camera and edit the control points of the camera in a second viewport.
so my wish:

allow dollyzoom behaviour with camera-control point editing !

(gumball, select single cvs, scale, scaleNu, scale 1d… don t work)

or does anybody find out how to do this ?