From a pilot but also ex mechanical engineer.
Nobody will be able to tell you because they don't know what your average flight profile is.
You basically have to work out what that is first.
Then work out how much fuel you burn with the additional weight.
Work out a maint cost per landing of the brakes.
Then do a comparision between the two types of brakes and work out how long it will take for the cost savings to pay off the investment and if you are going to make it back in the time you still have the aircraft.