He was the last thing I did last night. Perfect way to end a weekend on the new game.
I had come to terms with deflect, but that fight forced me to learn all aspects of the combat. Just learn a single move each time you face him if you have too. Eventually you'll know them all, and everytime you die it will be because you fucked up (and you will, lots). But the feeling of learning and getting better is overwhelming. And it just feels soooo good when it's all clicking.
Once you start figuring him out it's hardly about health management at all, you either are in the zone and dominating or a half second late, too antsy, etc. and get your ass beat.
Probably my favorite boss fight of all time, just because of the way how satisfying it was to learn and just slowly overcome it.
I used the loaded umbrella, you can also use prosthetic that can help whittle his posture. I didn't want to have to worry about doing an extra combo, and the umbrella made the arrows less of an issue.
Good luck!