''More significant is not to have same rotation''
That's debatable the Graupner Wiesel runs 3 in the same direction and the majority of WW2 Mtbs and rescue boats also did
Three props isn’t comparing apples with apples though
My understanding is that the outer props counter rotate outwards and centre either way. Fast forward with all props
Slow with centre prop and manoevering astern with outer props ? But still just as well to experiment.
If Graupner didn’t provide independent control of the props then it would be pointless to have the above set up and perhaps not important for a model ?