Flights to Dominican Republic from Newark with Amex Points?

Hi, im soon looking to go on vacation to the Dominican Republic and land either in Santiago or Santo Domingo. Whats the best way to maximize my points for a round trip flight for me and my girlfriend? Im looking for the best value. I know that the amex portal isnt always the best value, so which is? or how do i find it? If you can point me in the right direction, it would be greatly appreciated.