I found him really easy to fight (once I realized that you're supposed to strike the exposed red spots after uncapping them, I don't know why I didn't realize that right away), though that might be because my heat resistance is pretty high so his fire attacks were pretty tame. I didn't use bow at all, I prefer to take mine on melee directly.
I will say, your note of where the spots are is not correct. Only one hot spot is on the left wrist, the last spot is at the top of his staff. While technically attached to the wrist, it's pretty far away with how large the staff is. Your guide did help me though so I appreciate it nonetheless.
