I haven't but I am of the opinion that it is the full keel
that makes it a beast to back..... Actually I have found that it is pretty simple to back if you.
1. Turn the wheel
as though you were going to back any boat
2. Goose the engine
to get some speed backwards ( you "of course" will just go straight back or even a little the wrong direction )
3. Let off the throttle completely.
will amazingly figure out you want to turn the direction of the rudder
and will back the direction you intended, just like any boat.
However this only works as long as you still have momentum.
Once you lose momentum, just rinse and repeat.