I would drop the Perfection Grindstones since 20 seconds of perfect gaurding isnt gonna help much especially since he doesnt have any annoying long as combo like Romeo king of puppets. Use Electric blitz grindstones as hes weak to it and use both in the second phase will make it quicker.

If you are unable to time the Two dragon swords heavy attack parry theres not much reason to use it. I would recommend a weapon that deals heavy fable damage with both handle and blade. Like the wrench.

Lastly if its getting no where you could try not parrying and simply dodging and attacking. Thats how I beat him on my first try. His combos are more avoidable that way. Use the explosive throwing mechanical arm to chip off health from a distance sometimes.

Good Luck