Hi OG Ryder, sounds like your pretty onto it with the break in
That method on page 78 (originally) is a very sound way to break in the GO engines. The newer Gen 5.5 and GX Series motors are a lot easier to break in. If you buy one of those at some stage in the future, use the same method, but you can start to run it harder after half a gal or so.
Definitely heat the motor like Matt suggests, even after it's broken in if you can. Makes for a longer lasting engine. Make sure you always return the engine to BDC everytime you stop it too, always.