Turning the dizzy clockwise retards the timing. The "octane selector" is the slot with degree markings where the distributor housing is bolted to the block. Minor changes can be made there. Larger corrections are made by loosening the clamp screw holding the vacuum advance to the distributor body. Adjusting for spark knock usually only involves making a slight change with the octane selector, but if the scale isn't centered to begin with it might be necessary to make a rough adjustment to get things in the ballpark with the clamp ring.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!