The hobby shop person was trying to over simplify for you. Being an ABC engine, running that rich will not get it up to temp and cause premature wear in the TDC position.

Rather, run it rich, but not quite so rich that it 4 cycles. In other words, do not lean it out fully. Get it breifly 4 cycling and then just barely lean it into a 2 cycle mode. Do this for a few quick short runs with cooling in between. Then run a tank or two through it still in a rich 2 cycle. Enya's are very tight and long lasting engines, so be patient with your break in.

Ernie