If you need to get your back to the target in putting, you probably aren't doing the full shot release correctly in the first place.
Brian,
I thought the Runyan grip was intended to restrict wrist action? No?
Restrict the rolling or manipulation of the face open or closed more than is needed, rather than flex/extend?
I use a Two Thumb grip. Would this or a Super Stroke grip help this action? Seems to me that bit of wrist motion is pure flex/extend around the coupling point with these grips, very little roll.