Brake Wear Study
I remember reading a detailed study carried out by Lufthansa for their fleet of Airbus and Boeing aircraft, re costs for brake wear/replacement, fuel costs, engine wear, blocker door wear, etc.
The conclusion was for all fleets use 70% N1 Reverse and dependant on fleet, either Medium or Auto Brake 2 setting.
I caution this may well be out of date at todays costings as this study was carried out in the early 90's.