Yeah. She doesn't use PDR as her 50% reduction. I believe it's called Physical Element Reduction, which applies to all characters, even mages. However, mages can use Elemental Reset to remove the damage reduction.
Well, a 20k range (minimum) should be fine. If you are going for a decent time, I would say atleast 40k.
Also, they use a different damage reduction. Hilla's damage reduction is identical to that of Pink Bean and Empress, it's impenetrable for any class except mages.