Highest possible right hand ATK weapon?
It depends on whether or not you want to add scaling into your definition of highest Attack Rating. The Raw Malformed Skull +10 clocks in with a whopping 563 AR with no scaling. From personal experience, when power stancing and buffed with crystal magic weapon, raw malformed skull's L2 will deal nearly 1200 damage on Giant Lord regardless of which ng you're currently playing. On the other hand, the Great Club +10 does 567 AR at 50 strength making it a strong contender to the malformed skull at higher levels. Beyond that it's just personal preference!