AA,
That was my autopilot on my 22 cat. You can use this method but there are factors in determining how long your boat will track.
It's a question of balance. It depends on sea conditions, wind steadiness, sail trim, rudder attitude and people milling around changing the center of gravity.
Remember a fin keel will not self-track as well or long as a modified or full keel design. Fin types are easier to knock off track. With a fin your closer to a spinning top than a self steadying longer keel.
Using bungee or tightening Your wheel drag while finding the best sail set is a good way to get to know what your boat likes. While using this method, instead of adjusting your wheel, try adjusting sail trim to steer your boat. Also some adjustment to the rudder angle works. If your in chop this becomes more difficult, but practicing will give you a good idea of what the boat likes for balance.
CR