I rebuild these things and the best I could do is guesswork.
You need -professional- guidance from a repair facility that specializes in Onan. The end result is too much work, too much money and too much hassle to experiment with.
I, myself, would phone several huge repair facilities and ask their advice about the Onan rotor. If they and others report a problem, then you need to sit back a moment and make a decision.
If the selected repair facilities all go "Huh?" you will take an entirely different tack.
But that's just me...