Not really sure if you're serious or not, but I will assume you are.
Your damage is all over the place because unlike Jin, Kamu is a single hit, non-crit based WS. No matter what atmas you use, it will never crit, just like SAM WSs. Your only option is to stack it's mods, which for kamu is 50% STR and 50% INT. If you use atmas to help these, like atma of Minikin Monstrosity, you will lose a crit atma, which lowers your DoT. Any spikes you might see in abyssea may be from the random triple attack they may proc from Apoc. It's generally a shitty WS, with the only bonus of having the Blindness effect that stacks with Kuriyami. Typically speaking, if lowmanning abyssea NMs with high acc, prolly better to use and Evasion atma, like C&D.
Have fun with your pretty WS and don't worry to much about tanking. Shitty damage equals lower hate control which means the mob won't be looking at you, but a mage or better DD