You should always go with the C ratings.

While the amps given by standard and max give a basic idea of what the batteries will tolerate, the batteries capacity will decrease with usage.
That 4 amps max will change, monitor the capacity of your batteries during last charge to determine if you can still charge them at 4 amps the next time.

All depend on how long you are willing to wait.
Safe rates for 25R are from a few miliamps up to 4 amps maximum.