I used always say 300'. but an auto always has three components if you start early enough.
autorotational flight;- that's the same from 5,000' or 300',
termination area;- that's from when the first flare happens, a rule of thumb can be about one foot of altitude per every knot of airspeed and,
touchdown;- that's the same as a hovering auto or close enough.
In an R22, one can easily find that a nice tidy autorotational flight profile of at least 50 knots can be set up say at about 150' depending on DA, after a snap throttle closure from the hover at 300', well before the termination area with 2 up and 50 litres of fuel at least.
same in a '47.