I would agree that 45deg is the ideal, but to cause chatter I think they would have to be close to zero. Just my opinion from a practical thinking point of view, I haven't read the theory either. Perhaps someone could explain chattering at, say, 30deg, 20deg? I can understand the oil transfer bit but not chatter.
Correction: I have read at least a part of the linked theory.
Halfway down page three is a reference to a standard passenger car having what amounts to far wider tolerances.
The average aircraft engine of this type is not a race tuned high performance engine with every ounce of power squeezed out of it. Followed by a complete rebuild after the race. It was developed from an engine designed to drive a farm tractor.