Nice waste of power infusion then
But yeah, all common knowledge tips, the waiting for other abilities before pushing into phase you can even see in the paragon video, when they wait for the hammer to cast then dps just before the cast, getting an extra 1% or so off.
Personally we didn't not try to push for 1 meteor, instead saved heroism for phase 4 after both meteors had died. Since the dps requirements dropped so much in phase 3, was pretty comfortable without the heroism. Next to no dreadflame around at the time of the kill as well, was pretty nice.