Neither: you'll probably want SWF to take advantage of the higher damage modifier; max of 2x with PSWF+Offhand Versatility and empty offhand. Alternatively equip an orb and trade 0.25x INT damage bonus for "your Vorpal strikes cause you to gain Versatile Empowerment. (Your spells automatically crit for the next 5 seconds. Cooldown: 20 seconds)"
Remember than SDK chain attacks require a light melee weapon, not just a 1H weapon. So your best options are probably dagger w/VKF or kukri. [Or maybe short sword?] Though I kinda like the idea of using sickles with Sword to Plowshares for the closest thing to a
kusarigama.