The fight is a complete joke before last phase, and even then , just play with improved feint(? w/e its called) / leeching poison dont see any reason to take cheat death, and also , there is no reason to NOT switch to MC`d players , I was kinda like you aswell , but then I noticed people were slacking and did not break them off before the attenuation wich caused random deaths // Also , use pots normally - prepot + during lust (wich should be last phase start again - not sure what ur doing but in 10man we just nuke the boss and ignore the echo in a corner) - after lust ends boss should be at around 10-15%? from there on you just gotta play it safe and dont die to stupid shit.
glhf [also , drop your smokebomb/blind before MC`s come , not sure how this will apply when smokebomb will be a raid cd but meh]