Grinding HM in Tempest Trials
Is it efficient? Considering you'd have to have really good units to grind the level 40 map, you don't get as much HM per battle. Is it worth the Stamina it costs? Or is it just better to wait for the GHB maps or Grind them instead?
I've always found it to be a reasonably efficient way to grind HM as long as you're running one bonus unit and build a complimentary team. From a pure stamina efficiency perspective, the GHBs are obviously better since the cost is 0; but the TTs require slightly less babysitting and offer more SP through add'l enemies and more potential feathers through the rank reward.