I farm up a bunch of keese eyeballs (shooting a bomb arrow at a cave swarm makes this easier) and use those to target the heads. If you have fire/ice eyeballs those do elemental damage against their opposite types of gleok heads. If there’s an ice gleok head, you can use recall on the ice spike things during the last phase to get closer, but for the other gleoks I usually just keep trying with eyeball homing arrows until they hit.