I think it's going to be very rare that the two villains have missed this flop, so i don't think you'll be getting too many folds with the c-bet, although you do have an open ender and the backdoor nut-flushdraw.

Let's assume you have 8 clean outs, 2 non diamond aces and 3 non diamond kings and 3 non diamond 8's. If you hit on the turn your going to be value betting and not barreling/semi-bluffing, the only cards you can really barrel are clubs but i can't think of any clubs that will increase your fold equity on the turn if you get called on the flop bar the king but you would be value betting then. So there doesn't seem to be any good barrel cards, so you basically need them to fold on the flop which i think is highly unlikely or hit on the turn and you aren't going to hit that often, and you won't win the hand 100% of the times when you do hit either.