best setup for Barbatos

I'll be running Waver (with bond ce) + Merlin buffs + Leonidas (with bond ce) all buffed onto a Lu Bu NP5 with black grail bond 7 min. Should hit for around 700-800k which should be plenty to one shot him.

Similar situation to you; I'm planning to borrow a Waver and get my own Merlin to as high skills as I can, and then run with my Jalter. I'm hoping the damage boost from both, along with Anniversary Bride crit stars, will be enough to 1 or 2 shot.