The extension wobbling about above the head seems to suggest that you need to balance that main rotor.
How did you ensure proper alignment of the blades to prevent any forward sweep?
Why did you test at anything other than flat pitch? I appreciate that the blades are twisted but there is effectively a null point.
I will hopefully be constructing a cyclical disk controller to employ 3 axis control..
Which part of the pilot's anatomy will operate this control? He seems too busy 'rowing'...