Struggling to understand a sentence in the military manga 'Ibuki' I'm currently reading. Some top military brass are discussing China's military capabilities and how quickly Japan could deploy to the Senkaku islands in the event of a crisis.
"It would take us 20 minutes to reach the Senkakus after scrambling from Naha. With an aircraft carrier we'd close the gap, but there's a decisive difference in the number of aircraft we can maintain. China's aircraft carrier can carry 60 planes. Ours can only carry 15. それを五分以上の戦力にするには機の性能差と、搭乗員の技能しかない。"
I'm not sure whether the 五分以上 there is a reference to timing (ie the time to get to the Senkakus) or represents a proportion of the number of aircraft. If it's the former, the tricky part is parsing the それを五分以上の戦力にするには part. 戦力にする would be the verb that affects the object それを, but I always find にする tricky (textbooks say it means 'try for' or 'decide on' but I have my doubts on this one). Moreover, there's an additional noun 五分以上 that modifies 戦力, making 五分以上の戦力にする one giant looking verb.