Paladin/CoS Bard

Hi all, looking at a 2 paladin/10 bard for my next playthrough as I want a good face character/decent combat option as well. I'm pretty set on this setup, so my question is - if I want to maximize damage on divine smite, should I use strength or dex? I imagine it's weapon dependent, but if I want sword and board, would a finesse with high dex be best?