Small receiver packs on that charger I set to 6mV/C and a current up to 2A, no dead battery yet....
Regarding your 7.2V (racing?) packs, for NiCad you can go up to 2x its own capacity, with NiMh I would not go further than 1.5x its capacity.
With the 6mV/C it works fine for me with all kind of NiCad and NiMh batteries.
Speed is only fiction but a 130+km/h MRS4 is for real.