Water was not a consideration... Only fluids I carry are about 5 gallons in my fresh tank for roadside emergencies, and i carry that consistently on purpose to not change my balance. My grey and black tanks were emptied each morning before travelling... Again to not change my balance,and because I am cheap and don't want to waste fuel hauling dishwater around the country :)
We don't take much gear with us, and what we do take is generally stored in the same position on all of our previously successful trips. The only place we might have been a little heavier then normal is the pantry and that is centered over my wide-stance axels. Even clothing would have balanced out because the parents gear is mainly in the front or center coat closet and the kids is in the rear.