George Aldrich (RIP) had a lucrative business chroming peeled OS liners. He reported that of 300 engines only one (1) came from a CL flyer. He put this down to the fact that CL flyers almost invariably use much more oil (and mainly castor) in their fuels so he concluded that the OS ABN survives better with at least 22% oil. That's the advice of the engine Master, take it or leave it

To run it in, use a small prop (9x6 is good) preferably, use around 25% oil and set the mixture so it's running just barely above a 4 stroke setting for the first couple of tanks then slowly lean it out a little for the next few tanks. Contrary to popular opinion I don't think an ABx is a "one tank and go fly" engine although they survive this treatment surprisingly well.