Adam drake method does run the engine very rich, for 4 full tanks, just with an engine pre-heated, and then running 1/4, 1/2, and 3/4 throttle tanks afterwards all the while being quite rich.
i still take it easy after that until i can tell its fully broken in. and typically i do an extra tank at 1/4 throttle after i lean the engine 1/8 turn, then the same for 1/2 and 3/4. kind of a mix of the Associated method, and Adam drake method.
engines with rings will not have that same kind of mechanical wear, as the rings themselves will compress or expand as needed to keep a seal, and doesnt compress the piston while doing so.
i understand what you mean about the break in, but also thinking about wearing it in. as the piston and sleeve is cold(er) the pinch is tighter, so running for 3 tanks of fuel with the sleeve at its tightest compression gives the most mechanical wear. then as it warms up after those tanks of running really rich and you start leaning it in some. you have already had all that mechanical premature wear on the inside of the sleeve, that if warmed up first wouldnt be wearing. which being warmed up also reduces the stress on the connecting rod as it doesnt have to force itself through as tight of a pinch because everything is expanded.
ive been in the hobby for a decent while, and have never known it to be common practice to not use a gasket for the exhaust. i know the first time they heat up and expand it typically loosens the screws, so i always prepare to tighten them up, during first few tanks and have not had an issue since.
guess we each have our own ways of doing stuff. the most important things are to let cool between tanks, and to set your piston at BDC.