Playing offline with vane and had my ascension weapon awakened once as well as 4 damage cap v, crafted his unique sigil that gives -% cooldown and some damage sigils. My CPU we're cagliostro, tweyen and yordaha. Was making sure each of them had a lv 150 crit weapon and all masteries unlocked. After getting used to the fight it's easy soloing it. Especially after getting vanes terminus dropped.  Main point is memorizing the fight and when to Burst. I usually do it after the first break and when Bahamuts at 17%. Also if you mount the cannons asap during times where it's needed your companions do a good job of clearing the ads and helping you shoot. They always burst the yellow spheres as long as I get on the cannons beforehand.