I wouldn't sell this for less than 750. the 85h cal mentioned only went for that amount because that set% combination is undesirable and unpopular. this item is ripe to be someone's endgame NAB DF and it already comes with 2 spheres worth of native.
Even then, id say ab/d appeals more to the entry level DF users so I think around 450 is fair. Nab is cool but dark seems to be a priority for most people.