Andy, you are right.

My understanding is that under conditions that marginally favor detonation, that detonation is more likely
at lower RPM. As RPM rises, even though you approach, and pass, the torque peak, the danger of detonation
goes down. This is likely due to increased mixture turbulence, and decreased time for bad flame front to propagate.

Is this correct or old wives' tale ?

If I was targeting 12:1, I would have no chance, but at 10:1 I thought it would be managable with enough cam duration.
The other guys evidently had good luck at 230-degrees; I guessed that the long rod deal would require more duration
to stay out of detonation, maybe 240~250 min ?