>> Ok, so maybe I should conservatively assume 100 Melee Defense, not 90 or 92, is safe, albeit tentatively?
We know our dodge chance against orc youngS. But we can never guess the relationship of accuracy between different enemies, if we have never compared most of them. If orc young appears to be accuracy genius or idiot, your self-satisfying adjusted melee def value would be greatly biased.
Making the melee def higher is not necessarily the most conservative approach. You might waste melee def if orc young appears to be accuracy genius. If you want to be conservative, 82~83+5 (+5 is to combat increased accuracy due to greatsword and billhook) = 87~88 melee def