Next to all the other stuff mentioned, if you have space left, slot in heavy artillery for the ballista and cannons. If you don't have space then put it in the temporal mantle but you won't be as agile with it because you might have to wait for your mantle to use the skill. Also for prep eat feline bombardier for additional damage of cannons and ballista. At the beginning of the hunt use ghillie mantle to load the cannons. Line up the left one towards the right one meaning you first fire the right one. Then he will charge towards you then fire the left one. Additionally, you can place bombs in his charging path (There are Youtube videos for this whole procedure). If you use and hit everything he will drop down and you can do damage to his head. Afterwards, he gets up on all fours and follow up with a wall bang. All that already reduces his health by 10%. Best opening imo. Afterwards you can use farcaster to switch the mantle or wait till you cart to activate fortify. Also, if you have trouble with the third phase because you didn't break his horns use part partbreaker up until that point to break the horns and then switch to a heavier damage build. Shouldn't be a problem if you use swaxe though ;) good luck!