You can get a double hit with bombs in phase 1 by taking out a second bomb right after the first one explodes so that the first bomb's explosion causes the second one to explode. Listen to the music to time pulling out the first bomb, as Wart always takes the same amount of time to open its eye for the first time.
This video demonstrates a more damage intensive variation.
Jumpslash, then use one of the pots in the room or a bomb to get ISG. Once the eye opens, run through the bubbles and hit it with ISG. Quickspin to finish the fight.
This can also be done with Blast Mask.
Face the camera away from Wart, then turn back and target towards it to target without locking on. Once the eye opens, take damage from a bubble while moving to avoid knockback, then jumpslash the eye. This is precise with gilded sword, but not too precise with GFS. Quickspin to finish the fight.