With regard to Autobrake operation on the B744, my TM says ...
The RTO (rejected take-off) position provides maximum braking.
Also that ...
Landing autobrakes are armed by positioning the Autobrake Selector to one of the landing deceleration rates.
I'm afraid I have no information on the numbers involved. My guess is that on MAX setting, it is not a deceleration rate that applies but the maximum braking that surface conditions and antiskid will allow. However, I can tell you that, on landing, the MAX setting is impressive!
JD
