After Phantom Ganon I aimed for Ganon, since The Imprisoned is slow and takes a while to beat. Ganon: Arrows on his left arm, bombs on the right, Hookshot on the tail, Boomerang on the tusks. Special Attack on The Imprisoned's toes, save your Focus Spirit for him and hit X when he tries to get up after the Weak Point. By the way, time doesn't affect your ranking.