Try to spread out like this during plumes
(if you ain't too sure when plumes are, keep this formation too and dodge stuff that's currently happening accordingly)
Plumes do never happen at the same time as anything else but always shortly after 2 nasty things.
Plumes always happen after the Stomps.
Plumes always happen after Bombs (he does a landslide during bombs --> mountain buster before plumes, but the time between bombs and plumes is short)
So be ready to dodge plumes after stomps
And be ready to dodge plumes after bombs
Now for the plume dodge formation make sure to spread out like this even if there is no melee dps.
If there are randoms stacking on top of each other or whatever, let em do it, just pick a spot further away from them.