I've never understood the "don't lean below x000 feet" thing. In my TR182 I lean for taxi, otherwise the plugs foul. The only time I fly full rich is for take off and the initial climb to 1000 feet or so. After that I lean to CHTs of 400 or less - maybe up to 410 on the hottest cylinders. Much easier with a full engine monitor. Flying full rich (22 gph) would be pretty catastrophic for both my bank account and range, as compared to 14.5 which is what I can normally do without problems.