that would suggest that the twf or thf paladin doesnt have any doublestrike.
without shield you can get 10% from zeal or fighter capstone , 3 from spare hand (or 6% from random loot) and 3 from monk twist as well for 16-19% doublestrike.
and the most bang for your buck doublestrike wise gets thf since doublestrikes only apply to mainhand attacks.