[nuz69]

Theorically, a 3300mAh 6S has same run time as a 4S 5000mAh (both motor with same rpms), because its contains the same amount of electrical energy. Then weight should be then equal too, except a motor on 6S need less current discharge, so best configuration is 6S with 3300mAh. The efficiency is improved too, and moreover controlers like small current :)