I ended up purchasing the high thrust Yamaha 9.9. I mounted the controller on the cockpit seat with the shortest control cables available. So far it works great! The spacers on my bracket are working out well but it does cause the mounding board to be slightly off of horizontal. I think I may revisit that mod to see if it can be optimized.
Now I have completed a connecting rod. The Yamaha is equipped with a friction lock so that when I have the connecting rod attached I can release the friction so that it tracks the rudder. I haven't taken it out on the water so will report again later.