Yesterday my e-bay rudder arrived. I had noticed that there was a drive dog set on the pictures, but thought this was not included. It was included! and it was for an M4 propeller shaft! So now I have two dog drives and prop nuts
All of the parts seem top quality. The rudder seem light as I was hoping it would be but fearing it wouldn't. It seems adjustable in all the ways I could want. The only shortcoming seems to be that the lower screw is metal instead of Nylon. I would want the screw to be nylon so this would be the break point in case the rudder hits something so I'll probably replace that screw.
Another improvement would be to sharpen the leading edge to reduce drag.
Here are some pictures: