Good info here,...
Its important to understand that thresholds of detonation are dynamic in air-cooled engines where cylinder head temps mirror outside air temps and engine load. This means that one must be exceedingly careful in setting ignition timing to allow for variations in environmental conditions as well as fuel.
More information on this critical subject;
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Regarding your original question, all things being equal, I'd rather have a lower-compression engine with a good ignition advance curve, than a higher-compression one with retarded timing to accomodate the fuel you will use. The former is a lot more "eager" to rev,....