Also forgot to comment about the 4 man. You can definitely optimize the time with 4 ppl on, the composition normally is either 2 Volts (STR/DUR) + Nova + Nidus or Volt STR + Nova + Nidus + Wisp. You can optimize assasination and cache phase with 4 ppl since you get an extra hand to kill and look for caches; although 3 ppl even duo sometimes (Volt STR + Nova) work.