I think i have enough defense now.

Shield Mastery

That and 1 str = 1.2 def.

I've got around 1950 wdef on my Paladin, up to 6200 or so with Iron Body + Shield Mastery.

Also I can confirm that equip %def bonuses are additive with Shield Mastery (since I have 6% def on my helm). So... 306% def.