Dar,
I don't consider any engine even ABC broken in after a few tanks. I have seen many that would not idle well below 2800 till running in the air for several tanks. I recall an early Super Tigre ABC that took almost as much fuel as a ringed engine, it wouldn't idle well till I ran almost a gallon of fuel through it. It would shake a bit when idleing below 3000. Onr of my TT .46 engines took over a half gallon. Both would stop near TDC if idled too low.