Hugh,

We will have to agree to each hold on to his own views on this.

Even if a tapered-bore engine stays in one piece after a slobbery rich break-in (and most sport engines will not immediately self destruct), the amount of wear incurred by the piston crown as a result, is equal to many hours of normal use.
Much more wear than a rich, two stroke break-in will result in.

Even Dub Jett advises of a very short four-cycle period (1 minute, I believe), just to take the edge off the extreme, finger breaking TDC tightness, his engines are manufactured with. Most sport engines don't need this at all, but I have seen some MVVSs that did.

He is also the strongest supporter of making sure a TDC pinch always exists in any engine considered to be in good shape.