yes, plenty of theories out there to play around with. but there are a few fundamentally same ideas floating about which makes perfect sense (josh cyrul's break in method is pretty near ideal IMO).
1. every engine is different; meaning each have their own needle settings. counting out many turns out will only give ball park to start an engine. also 2 turns out high speed and 1 turn out low speed is NOT a ball park figure for every engine. case in point: most novarossi's will run over 4 turns out and from my experience the new traxxas engines run over 3 to 3 1/2 turns for best starting (here in New England anyways). when in doubt check with a manufacturer resource for correct base setting.
2. break in is about allowing the parts to fit. letting it idle for numerous tanks is a sure fire way to decreasing engine life. RCCA covered this topic very well, so i wont get into it.
whatever method you use, keep in mind again that break in allows for parts to mesh and fit. preparation is important and you should take apart a new engine to clean it out and make sure there is no scraps left over from manufacturing. temperature gauge is your best friend as it will show if you are running too hot or too cold. as long as you are not going to the extreme (babying too much, or not babying your engine enough) you should be ok.