I think it really depends on the profile of your botanicals. For my particular recipe, anything after 77% ABV has an undesirable "cooked" tone to it so I usually stop it by then, though in theory there should still be more hearts to collect at that point.
thanks for the input - can you elaborate a bit more on why you chose to remove your dephlegmator? i was told it should help in creating a smoother/higher quality distillate, but i'm wondering if its actually worth my while if i'm already using a good quality GNS. I'm also thinking it could potentially strip away some essential flavor components. What was your experience with it (besides slowing you down)?