ill tell u my oppinion, for 10D+ theres no chance for fire/cold ill tell u somethin i was best spear hybrid at hercules on 9D fire90 heuksal 90 light 60 and cold 60 best build with 80% balance as i remember
lets see the following things
light-> 18% magic dmg 300% dmg nuker
fire -> 10% from passive and 9% from buff phy dmg and 330% nuker dmg +better imbue +better crits
i think that the best build now,making somethin like mine one its 100 fire 100 heuks 60 cold and 40 light
fire still the best

make it at 80% will be a nice build pm me if you need ask somethin more