Closing the intake valve later to reduce CCP works at cranking and low RPM, but its effect on anti-knock is gone well before your torque peak.
Controlling cranking compression can help with pre-ignition. Compressing a gas increases its temperature. Starting with a colder intake charge also helps.
Detonation is an uncontrolled combustion event which occurs after the spark event. Chamber / piston shape, spark plug location, and quench distance can help or hurt.
Either way, you want to avoid hot spots in the chamber and on the piston.
There are a bunch of dynamics that I don't understand. As RPM goes up in may reduce the chance of detonation, but not sure how the relationships of Time (decreasing with RPM) vs Air/exhaust flow (increasing with RPM) vs Engine load (how fast the RPM is changing.) I think the slower reving engine (think heavy truck) us going to build more chamber heat than a light vehicle with the same power.
So it makes it hard to compare just compression ratio vs. octane as there are a bunch of unknown variables.
