I find the code example given to be rather complex. Just to find the neutral
point, I would write a 4-line for-loop program that stepped the servo pulsewidth
from 1450-1550 usec in 1-usec steps with a 100-msec delay at the end of the
loop and a Serial.print(pulsewidth); statement inside the loop.
Then I would know the neutral point in about 2-minutes.