I have a mystery ranch pintler that is the perfect size for me for a 1-2 day hunt and I have a MR terraframe 80 Liter bag that fits on the frame for when I'm going out west.
Those two bags seem perfect to me but I have issues with the MR Frame fitting myself and my son. We both have long torsos and our MR packs have almost no lift for me and none for him. I have a 21" torso and he has a 23". I would love to put both of these bags on a Kifaru Duplex lite.