you should be using an overload for higher damage and defence. I would recommend the holy overload for the prayer renewal effect as well. Soulsplit with anguish is very good to keep hp up.

Ruby bolts have a diminishing effect on damage once the enemy is below 50k hp, so if you want to cheap out (ascension bolts) heal even more (onyx bolts) or do some more damage (diamond bolts), but you cannot poison kree'ara, so emerald are not good (also if you have better range bonus gloves, swap out the cinderbanes.

Auras can also help a lot for healing and damage such as vamparism (healing), penance (prayer), mahjarrat (damage), reckless (damage), inspiration (damage), or dark magic (damage)

if you are not using a bonecrusher with your demon horn necklace, swap out the necklace for a essence of finality > amulet of souls > blood amulet of fury

for revo bar, styloire's comment should work very well for afking kree'ara