Ages ago when I taught sailing (using Ericsons by the way) we developed the technique below:
Don't try to maneuver backwards with the throttle wide open.
Burst the throttle wide open for 5 to 10 seconds, which should get you to around 2 knots ~ 3 feet/sec.
Then coast for 20sec = around two boat lengths.
If you are not far enough out, give the throttle another 3 or 4 second burst.
Not foolproof. And requires practice.
Find some water with sea room on a nice day, throw something that floats (a cushion or empty anti-freeze jug) over the side and practice stopping at it fwd, back, from left and from right. This is by the way part of a man overboard drill, picking up a mooring, dropping your anchor exactly where you want it, and retrieving your Tilley hat.
Also, try it completely under sail.
--Steve