Breaking in an engine
 

Run it in with short runs at full throttle with the needle set just on the lean side of where it's about to change note in a 4 stroke. That's about the only way to describe a rich 2 stroke setting :) Personally I'd give it at least 30 minutes bench running before flying with it.
There's a couple of things you can do to maximise the life. The first is to use more oil than the average fuel has in it, mainly because it's a bushed engine, and I'd have castor as at least half the oil content. George Aldrich always recommended 22% oil for the LA's.
The second thing you can do is learn to start it by hand. An electric starter can do enormous damage to an engine if the engine isn't primed properly first so it's ready to start straight away. And the only way to get the feel for what it needs is to start by hand.

Breaking in an engine
 

The above is basicly right...

The LA needs to be brought up to normal operating temperature durring its break-in, and not allowed to cool excessively while running. Tune for max rpm, then open the needle 1/4 turn. Don't go below 1/3 throttle for the first 8 oz tank.