The repeated cool down's accomplish nothing. I have alway's simply ran a tank or two at a rich two stroke. The cool down cycling is a holdover from the first ABC engines which needed anealing, though this didn't do much for that either. The taper remains after the breakin , its just that you have worn off the top of the piston to fit the taper at the top of the cylinder.

Though your break in procedure will do no harm. Just makes it more complicated.