I found this flex shaft and bushing from a place called Wire Monkey. $8.75. Eliminates the alignment problems from retro-fitting a rear pot installation.
The bushing turns the 3/8 hole in the faceplate into a 1/4" port for the shaft. The Flex Shaft is a piece of braided spring steel with 1/4" females at each end. Like a "U" joint.
Very simple and elegant solution.

• Wire Monkey