Jerry,
I have a setup that has a bungee to centre my steering, it's attached to the cross arm.
The tension in the spinnaker pull up/pull down line tensions the bungee and holds the boat on course.
Basically only works when I'm single handing and the spinnaker is in the process of going up or down.
So my two hands pulling on the halyard also indirectly keep the boat on course.
If the spinnaker is not in the process of being pulled up or down ie. normal manouvering the bunger is quite lose and has no influence on the steering of the boat.

As far as the debate about catching your boat if you fall off. Ever tried it? Unless the mast has anchoured the boat by sticking in the mud I have never really been that quick a swimmer. If there is enough wind to cause a capsize, even on there side, they drift faster than I will ever be able to swim.
Anyhow in the event of falling off the bungee system I have has no influence on the steering at all and the rudders a free to do what ever they want to.

Regards,
Phill

I know that the voices in my head aint real,
but they have some pretty good ideas.
There is no such thing as a quick fix and I've never had free lunch!