From my times there it seemed that the winds tended to be upstream or downstream (or not much wind). I would think you would want a smallish boat that performs very well with an easy to use spinnaker system. I don't know candidate boats well enough to recommend one, but something with a self-tending jib would be good.
In South Africa doing lots of boat stuff. Departure north from Cape Town around December 15th. Arrival in the Caribbean around the beginning of February, after 5300 miles or so.