Thank you. Will look into settings. Think the 4 six volt batteries are as large as they come.

there is no setting to change battery other than battery type
you can change performance modes , there are 3 modes, mode 1 is battery saver mode but all functions are in soft mode which are slowest.
you may be able to set motor performances in custom mode settings to change motor ramp up speed and braking options to try and dampen motor performance but that will take some testing over time to get it exactly how you want it.
There is one other option, see if there is another battery with more AH rating, if you can find a larger (higher AH) battery it will last longer.