On your Spec packs, if you are running outside, charge at 5 amps with a .03 peak detect. For carpet, charge at 7 amps with a .03 peak detect. Discharge at 15 amps with a .90 per cell cutoff (3.60 volts.)
You also need to get a single 1157 automotive bulb, and discharge the battery with that after discharging it on the GFX. Take the bulb off as soon as it starts to go out, and go straight to charging.
Hope this helps!